I've impulsively bought about 10 SAKs in my lifetime, but i've recently realized what's my favs according to a specific philosophy.
I prefer a SAK to be the traditional camping/boyscout/military folding knife. With this in mind, I believe it should first have 2 blades, the second for a backup.
A can opener for your meals. and a really usefull "woods" friendly tool, that eliminates most of the junk offered with SAKS. Yes the scissors are handy when EDCing, but if your other 2 blades are sharp enough its not needed unless you HAVE to cut in a perfect straight line.
The most useful extra tool I have found with SAKs is the wood saw. This thing is a monster worker. yeah, you cant cut down a tree with it, but its handy for fabricating notches in branches if you're building a shelter or such.
If you have too much stuff, it gets too wide, so the HIKER with the saw is what i'd want, especially since it has a phillips screwdriver instead of a cork screw, and this makes it slimmer.
I also have a vintage Hoffritz WAITER with just a blade and cap lifter plus corkscrew on the back. I hooked up a small light to it and its my non offensive "go to a party or bar" knife. You'll be the hero if you have a bottle opener handy.
So to recap:
1. HIKER
2. WAITER
in fact i wouldn't mind having doubles of these.