I'm not sure I'd recommend a 64bit distro. I can't speak for the others, but I know with Ubuntu, getting some simple things to work(like web plugins, flash, etc), requires a bit of hoop jumping. It can be done, but I just found it easier to stick with 32bit for the forseeable future.
You're hard drive isn't to large, I've got a 500gig IDE that works fine, as well as a 500gig USB that works fine.
Suse supposedly has pretty solid 64bit support(but I imagine all of the above is still an issue)
Last edited by IndyGunFreak; 08-25-2007 at 09:58 PM.