[wlug] Where to buy and get good advice on computers which will operate with Ubuntu Breezy

I am considering buying a new bare bones system but wish to make sure it works. I use it mostly for Photo editing with the Gimp and some other graphics programs. Would an on board graphics or an additional Video card be a good idea. I was also considering getting 1gig ram. I wanted it to be a Linux only box. Also should I choose a 64bit system.