It all depends on what game, the resolution, and what settings are used. In many tests, the X800XTplatinum is the easily the king, especially with AA&AF being used. IMO if I had to spend $500 on either, I'd get the XTPlatinum over the 6800U. But if the 6800GT was avaialbale for $100 less than the others, I'd switch to the GT for sure. How much of my money is the ulta worth over the GT, maybe $30. The X800XTPlatiunum is maybe worth $50 more to me. Just my opinion of course. You can't go wrong with any of those 3 cards. If you find one in your price range and need an upgrade, go for it. If certain games mean the most to you (Doom3, HL2, FarCry, Etc.) look or wait for benchies that best show what will meet your needs.
Edit: Actually paying over retail price doesn't sit well with me. So the cards are all good, not taking into account the cost. Only you can determine if any of them are worth $400-$500, compared to say a <A HREF="http://shop4.outpost.com/product/3628345" target="_new">$176 Radeon 9800 Pro</A>.
ABIT IS7, P4 2.6C, 1GB Corsair XMS 4000 Pro Series, Radeon 9800 Pro, Santa Cruz, TruePower 430watt<P ID="edit"><FONT SIZE=-1><EM>Edited by Pauldh on 07/27/04 03:22 PM.</EM></FONT></P>