$750 for either an all-matching Carbine or Garand- those are like prices from quite a few years gone by. In the average of things, I'd say it's a rarity to see either one in all matching condition. Is there a chance you can inspect them more closely?
For collectibility, I'd probably go with the Garand too... especially if I had the chance to check the throat errosion and muzzle errosion. The Carbine- those barrels get used and abused too you know.
Schuster (sp) gas plugs are available for the Garand so you can shoot a much broader availability of ammo. Otherwise, it's CMP ammo, or off-the-shelf M1 ammo which is kinda high.
M1 Carbine ammo is getting more plentiful and cheaper for the time being. I see no reason it should change. While there is an initial sticker shock- one must keep in mind most of it comes in boxes of 50 instead of 20.
All three are tons of fun to shoot. But the Norinco (and any M1A type rifle) is not as easy to lay hands on, at least in my part of the country. And I believe they are much less particular about what .308 ammo you feed them. There are some compatability issues with Norinco's I think. However, it's not impossible to keep any of them up and running- or to have things done such as barrel replacements. Criterion makes barrels for both the M1 and M1Carbine, I don't know about the Norinco.
Any way you look at it, you're in a tough spot to choose one. Now if the U.S. rifles truly are original and haven't gone through an armory rebuild (which I suspect is unlikely), then I would be all over the Garand like a fat boy on a doughnut.
Rednecks... Keeping the woods critter-free since March 2, 1836. (TX Independence Day)
I'm going to use the words "clip" and "Long Colt" every chance I get. It grinds my gears to see new members attacked when we all know dang good and well what's being refered to.