With my 8 years on-off-on-on experience doing mickey-mouse construction I give you these words.
Firstly, buy a cheapie boxcutter-type knife, I gave up on the little folding guys because the handle was just too short and hard to hold. Go full size. Carry it with you everywhere, give it to people who need to borrow a knife and use it yourself if it works better than your folder. Shrug your shoulders if you lose it or it gets stolen.
Secondly, take off the pocket clip and get a sheath for it. If you ever get stuck doing a lot of cutting that sucker will give mean blisters and cause some pretty decent pain after the first few cuts.
Then, get something that is easy to sharpen, with a thinner edge (we have real prybars, don't need one with an edge) and a safe handle. Also realize that if you use your knife hard you won't see the sunny side of a shaving edge after the first cut of the day. Make sure your knife is cheap enough that it won't kill you when it gets lost/stolen, because you can't really do much when your 45 year-old 275-pound co-worker gives you a dirty look and says he already gave back your 120$ folder and you must have lost it.
I used a Manix for a little bit while working on the job (carpentry, masonry, government work, etc.) and quickly found that if at the end of the day my choice was between a 3 minute walk to the truck to get a cutter or using the Manix to cut something unmentionable (thin steel bands, bags o' quikcrete, tree roots, etc. again) I would always use the Manix. The problem was that sharpening it was such a pain I eventually sold it and went to a BM550 Griptilian in 440C because it took about a quarter of the time to sharpen the 550 over the Manix in the morning or at night before going to bed.
The three knives that I have always come back to have been the CRKT Lightfoot M1, the Spyderco Pacific Salt and the Benchmade 550. The first two I have purchased 3 different times to replace stolen knives or knives that were retired from use. Also, oddly enough, the victorinox 3' paring knife, in plain edge or serrated, makes an excellent construction knife. The only reason I don't use it more is because I'm too lazy to hunt up a sheath for it.
I did toy with the idea of a "super-knife" but I just like using a knife that is mine and giving it some real hard use.
P.S. The BM550 powers through drywall like butter if you whack it with a rubber mallet. (abuse? where?)