Tom's Hardware is Objective.
Here's the Graphics Card Hierarchy Chart. It directly answers your question. One must jump up 2 levels to see a difference. For you that means GTX480 or HD5870 or better.
Hierarchy What's the best for the money? Being an ATI Fan I like HD5870

However, Tom's is more even handed.
Best GPU for the Money We're about 6 weeks away from the first HD6xxx cards. Prices on everything current are rumored to drop in a big way by then. Nvidia has nothing to compete directly -- so they will be dropping prices a lot -- starting soon, it is rumored. Thus, might want to wait a few weeks to get the best deal.
EDIT: Two like minded replies, I see

Edited by Allen (09/07/10 10:36 AM)
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ATI Sapphire HD7970 OC - Eyefinity 5760x1200 24", 1xDell-U2410 H-IPS + 2xHP-ZR24w S-IPS, Extended 23" Samsung cPVA, Ceton InfiniTV 4, Bulldozer FX8150@4.5GHz w/Swiftech Water Cooling, 16GB GSKILL PC3 @1866, ASUS Sabertooth 990FX, Corsair 120GB SSD, WDigital + 3x Seagate + Hitachi + 2x WD Ext = 10.0TB, Sony DVD, OCZ ZX 850W PSU, CoolerMaster HAF922, TM Warthog HOTAS, TM T-Flight Stick X, TM Cougar+FSSB & CH Pedals, Saitek X52 Pro & Pro Combat Pedals, TrackIR5 w/TC Pro, Windows 7 HP 64b