I like the standard GI shape. There's some nice variation out there in terms of panel thickness, but I'm not really one for thumbrests and finger grooves. As to material, I really don't care much from a practical standpoint, but for wood, there's a little voice in my head that lobbies for American walnut on an American handgun. As for aesthetics, a weapon platform with a history that long brings personality to the party. On an older gun, commercial or GI, the individual gun has to tell you what it wants.
I like G10 on a modern one, but they did teach me a useful trick - the stuff has ZERO compressibility, so there's ZERO push back against the heads of the grips screws, which therefore tend to work loose. I now install teeny little o-rings on my grip screws to act as lock washers.
Even on the modern 1911's, I still like to apply a sense of "Roots". On my 21st Century Springfield with it's rail-mounted flashlight, G10 grips, epoxy paint finish, and night sights, I installed a mainspring housing with a 19th Century lanyard loop that I have no intention of putting a lanyard on.