Finding a "perfect" tool is pretty hard- each one has strengths and weaknesses over each of the others, and that's great because it means that you can always find a tool that really works for you, or at least for a specific purpose.
Unfortunately, I like a balance. For a tool to be most worthwhile for me, it has to perform EVERYTHING well, and the closest to that dream for me so far would be the Spirit. However, the Spirit is still missing a few things that I'd like to have, so starting from scratch, this is what I'd like to see in my "perfect" multitool:
Pliers- Gotta start with either the robust head of the SwissTool or the blunted and virtually indestructable head of the Wenger SwissGrip, although with the compound leverage feature of the PowerLock.
Handles- Spirit all the way....
Tool Locking Mechanism- Spirit/SwissTool
Metal Saw- Leatherman Diamond file/saw, only preferably a little thinner. The diamond file is awesome, but it's a little thick to try to cut with.
Wood Saw- Wenger SwissGrip, because it's HUGE!
Main Blade- Toss up between the large liner locking clip point of the Wenger and the "razor" type sheepsfoot on the Spirit. I like a big blade, but the sheepsfoot gives you the most edge, and what do you need a point for on a tool blade? Not likely to be poking anything... Of course, adding in the OH feature of the Wave would be a serious bonus too.
Scissors- Leatherman's folding scissors like the ones on the PST II, or the huge ones on the PowerLock, only turned around so that they aren't blocked by the opposite handle
Awl- Spirit again as it is a handy awl and it integrates the hook, which comes in handy when you least expect it
Can Opener- Victorinox again, since it incorporates the teeny screwdriver. Of course, so does SOG and a few others, so any tool using that style is fine.
Bottle Opener- Victorinox again, for the bigger screwdriver, but otherwise same as above.
That's pretty much about it. What does everyone else think they would need in a "perfect" multitool?
Def