okay, this is my list of things you should get, but not necessarily own for the long run. When I tend to think of "Busse's to get" I don't necessarily expect all of them to be keepers, I think of them as stepping stones towards understanding the greater busse catalog so that you know what you like the best.
MOAB - It's a massive knife with an incredibly thick edge. It is the biggest knife busse has produced that wasn't pure custom. You'll know if your okay with a) that much money in one knife and b) something that heavy
TTKZ - Best chopping handle busse has ever produced (to me) in full tang. It stays locked into one position and gives you a solid grip because of the even index to pinky heigth and the overal shape. The one problem is that the edge is a low (50%) FAT convex saber. This means that it's incredibly heavy on the front end and incredibly thick. Where the MOAB is thick right behind the edge but has a full flat, the TTKZ is thick behind the edge
and gets thick incredibly fast because of it's grind. If your willing to send this in to garth to get the grind thinned out it will be the best chopper in the catalog.
KZII - You should get this to compare to the TTKZ, and the NMFBM. The grind is better than the TTKZ and it's blade shape may be more to your liking (or less). The main issue with the KZII is the handle. It is built more like the fusion handles with a big tennis ball in the center. the palm/finger swell is severe and the height difference between the index/pinky position and the center of the finger/palm swell is to much for me. It makes it bite into your metacarpals (hand bones) when you squeeze hard on it. Also, the rear pommel swell is too up swept and it smashes into your wrist/arm when you chop past a straight line with your arm. BUT - you'll have to own it to know if thats the case with you. If you like wrist snaps while choking up on the handle - the kz2 is better then the TTKZ.
FFBM - This is worth getting to compare to the NMFBM. It's like the MOAB in it's edge structure, where it's got way way way to much metal directly behind the edge, so it doesn't want to sink into the wood, it wants to smash it like a mallet. I consider it kind of a not-ideal set up like other busse's because it doesn't feel like a 'total one piece knife' like the HOGFSH. Instead, it feels kind of like the CGNMFBM in that it feels like a plate of steel, it vibrates like a plate of steel. For it's length, it is a heavy heavy knife.
ergo battle mistress - You should get this just to try out the ergo handles. The pinky position is too tall and the curve on the palm to severe, but it's worth trying 1) because of it's history 2) because it's more neutral then most other choppers in it's size because of it's HUGE pommel height and 3) because some people love the ergo handle.
HOGFSH - This is one of the most perfect feeling designs I've handled from busse, in a standard scale configuration. It feels like a 'complete' design, not to blade heavy, not to handle heavy, not like a plate of steel or like a sledge hammer, it feels
right.
AK47 - This is worth getting, to me, to figure out if you like the sword configuration or not. This has too thick of an edge, to low of a saber grind, and to wide of a convex curve to be reasonable for general use. It also has a strange balance for a sword - it's not the choppers you get from Himalayan Imports, and it's not a nuetrally balanced highly perfected weapon like a katana from 1675 japan. It's a weird mix that for me wasn't really worth it. But others love it - you won't know until you try it.
RUCK KENSAI - custom shop - I would like to try the Ruck Kensai to see if it can be used as a chopper/machete even despite it's way-too-thick grind. BUT the real reason I see to buy the ruck kensai is to have it's handle shortened to either a one handed grip or a short 2 handed grip and have it's grind brought up to a full flat by the Custom Shop. That would make it a one of a kind INFI machete.
Gladius - Just because you need one. Everyone who can afford it needs one.
Dagger - because it may be the only time you see one come through from busse.
Crash Rat - The one Busse kin axe. It was too thick behind the edge for me and wasn't as 'axe like' as I was hoping for, but it's worth trying. It is very heavy because of the amount of full thickness stock present. I have always wanted to rebuy one and remove the spike and finger grooves and then add a thin but round set of g10 scales to cover the entire handle length.
pauls hatchet - I wouldn't keep this, but you should try it out. 3rd gen handle with a mini hatchet head. My issue was just that the edge was very small and there wasn't enough weight in it to get good chopping force, but I was assuming I'd just use it on chopping wood and not in the kitchen. If that had been one of my requirements it may have been a lot more appealing. It's a unique little hatchet thats worth trying at least once.
SAR 8 - This has a handle that some people really love, others find to be to large. It's a nice package because it's got a pommel flare the keeps your hand from sliding back but it's overall package is less tall then other choppers in it's size. It's like a basic 9 thats had a lot of metal put into the handle.
DSSF - This is like an elongated Boss Jack. It's the most compact chopper of its size that your going to find from any of the busse kin. Excellent chopper that saves as much weight and size possible.
LE Choiless Boss Jack - A (slightly less than) 3/16" version of the Choiless Boss Jack. I haven't handled the edge so I don't know how thick it is but it is probably worth trying to see if you'd prefer a thiner variation on your Choiless Boss Jack proto or cgcbj. If you don't have a Proto and want a thicker version of the cg

p) it's worth looking for a proto.
mini sus scrofa - This is one of the thinner slicers in the busse catalog that I think a lot of people skip over for something like the boney active duty. The benefit over the BAD is it's unique edge structure. Personally I woudln't be willing to keep the knife without either sending it in to the custom shop to remove the choil or modifying it myself to do so, but I think it's something that people should try out at least once if they have the money.
boney active duty - Worth having because it's the highest hardness busse can get INFI, and it's thin. I don't like the active duty handle because the palm swell is too severe, but I'd like to try it at some point because of the change of heat treat and edge thickness.
CABS - Only thin choiless knife busse has made. I didn't end up keeping mine, but thats only because I switched to a CABJ. Had it not been for that, I would have carried it until a CABJ or comparable came into existence.
basic 5 - One of the better designs busse has come up with. It's M-INFI but it's super light for it's overal size. It's also one of the best edc sized knives for sub zero environments because of it's reciprene c handle.
basic 7 - I felt nothing for this blade, like... Didn't love it, didn't hate it, didn't feel
anything. It just kind of disappeared in my hand, so it was hard to feel anything about it. BUT, it's like the basic 5 but long enough to chop and with more edge for general cutting tasks. I think the basic 5 to basic 7 transition depends on the person, where one will feel to small for one person, the basic 7 will feel perfect, and for that basic 5 person the basic 7 will feel to large.
SHBA - I found the finger swell to be to severe and the overall package to be to handle heavy, but some people love this knife. It's worth trying to see if your one of them.
scotch dispensor - one of the small skeleton handles Busse has produced. Strange handle, similarly to the war boar. I haven't tried one, but I think if your going to have a collection you should have the stand out 'weird' knives in the mix.
war boar - Only busse kin karambit. It's got too severe of an angle between handle and blade to be useful as an edc, and it's seat belt cutter serrated upper edge makes it both less likely to be legal and a little harder to use as an edc. I also wouldn't have put a finger ring in the design. BUT it's super unique, and you might like it.
skeleton key - Tiny little skeleton design that is very compact. I'd prefer less of a choil, but it's one of those awesome knives that just kind of disappeared in the public eye over time.
rat tail - One of my favorite busse kin knives of all time. It's the most compact mini edc I've seen. It's got a very small choil, a super compact handle, a short compact gaurd that minimize the distance between your index finger and edge, it's thin enough to be okay as an edc but thick enough to be able to pry with and it's highly pocketable.
If you can get anything pre-straight handle days, any of the desert fighters, proto badger attacks, or unique field grades they are excellent for a collectors collection. And you can be one of the few people to find one and then take it on as a user.
Last ones if you just have lots of money and want to have them (I don't suggest getting these for use)
Force 1 - weird. The front is a puuko style zero edge going from .220 to edge in about 1/4", making it very very very thick, even if it's "shaving sharp". Great handle and length, but weird tip grind.
pt5 - weird. Same as above, but instead of the special forces handle this has the ergo handle. It's got to short edges and the same puuko style zero edge on the tip.