I'll chime in on the side of Micarta; the stuff is virtually immune to weather and shock. Because of its larger threads, canvas Micarta is very "grippy" -- there are microscopic little hairs all over the surface that keep your hand from slipping even in oily environments. Canvas Micarta does not take a shiny finish.
Linen Micarta will shine up nicely, and is still very grippy when wet. It's my favorite for those reasons. I've had paper Micarta actually shrink over the years and leave pins above the surface, which suprized me.
Dymondwood is basically the same thing as Micarta, only substituting birch laminations for fabric or paper. It comes in virtually every color you could desire and is a very well-behaved material. From a collector's viewpoint it's not very desrirable, though, as there's a connotation of cheapness that is in my opinion undeserved.
I haven't used G10 or carbon fiber, and until I get a damn good respirator I won't -- the thought of all those little fibers floating in the air headed for my lungs is somehow more scary to me than the phenolic vapor from Micarta. This is probably not very rational, though. All these things will probably hurt you over the long haul if you don't protect yourself from them.
One final word: wood, antler and bone have made fine knife handles for tens of thousands of years -- don't discount them. They are beautiful, hold up well and have a much "warmer" aspect than any synthetic material could hope to. Just my 2c.
Good luck with your knife making, it's great to have a new maker thinking ahead like you are.
Dave
