I'm not too familiar with ATI as I have always used nVidia. I'm currently running a 7900 GT-OC from BFG. I got it about a year ago and it was top flight then and set me back £300.

I would always advise someone to get an old top flight card than one that has been made for the budget market. It all depends on how much cash you have... and without that info it's tough to be more specific.