I'm 6'0" and I find my M16 to be a good all-around size. But there are really two things to consider with an M16 versus your ability to use it: barrel length and stock length.
The barrel length makes it a bit unwieldy in really tight quarters, but it's fine in open space. That said, it can still be used effectively in close quarters if you tweak your shooting position. By tweak I mean either hold it with the stock over your shoulder or under. You can't use sights or (most) optics this way but if you get used to the gun you should be able to tell where it's going to hit.
As for the stock, the full stock on the M16 is up there with the longest stocks on any gun. Comparing it side by side with an SG552 and an AK, it has about 1 and 3 inches over them, respectively. You could always replace it with a retractable stock though, if you find it too long.
I didn't really say much about internal upgrades because I don't really know much about it and haven't done anything to mine yet, and because it seems to have been aptly covered by everyone who's posted before me.
The war between the sexes is over. We won the second women started doing pole dancing for exercise.
Last edited by Huron; May 15th, 2009 at 21:14..