I spent over $3000 on my rig, custom built by me. Took me about 6 months to get it running from start of design to testing finish. Went through 3 motherboards and 2 processors until it held.
4.5Ghz i7-920 on water
8GB of 2GHz Corsair Dominator GT
Intel G25-XM2 80gb SSD's in Raid 0
blah blah blah
I have since added a second 5870 to the list (pictures were from the initial build).
I play on a 30" Apple Cinema HD with everything maxed at 2560x1600. Wandering around playing with my willie gives mes about 140 fps, in raids (10 or 25) I average between 60-90.
I wouldn't worry unless your frames drop below 20. Tho I will admit the old school designs are quite attractive at full spec.
http://picasaweb.google.com/stormthegeek/LiquidKhaosV2#
I love it. She crunches Fold when I'm at work.