Sorry for going off topic,
I thought to add my own opinion after seeing a lil argument going on this thread.
I currently have a 8800gt.
If I had money for another vga, I would go for a another 8800gt if I have a sli mboard, bt now I don't have any, sold it to the thread starter
So the next best choices for me are (with a cxfire mboard)(to play games in 1280*1024 or 1680*1050 resolution)(all details high)
HD4850 in cx fire
HD4870
GTX 280
GTX 260
9800 GX2
HD4850 in cx fire is a good setup in cx fire supported games, else it doesn't perform as good as others compared with the price. and there's a heat problem with stock cooling when ocing.
HD 4870 gives better frame rates, good quality to its price, this is recommended ,and can pair with another 4870 in future if using a cxfire mboard.
GTX 280 ties with GX2 in most games in low resolution and no heat issues, micro stut issues. 280 FTW. But completely out of the budget and useless if gaming under above resolutions.
GTX 260 ties with the 4870 in most games bt some times not as good as 4870 and sometimes better than 4870, it depends on the games you're playing. but Bang for the buck. but useless buying if you have a cx fire supported mboard and if not willing to upgrade to a new generation soon.power consumption is bit high.
9800 gx2's both benchmarks and gaming frame rates are better in most games ,it outperforms the 280 and and becomes the best out of above mentioned cards
sometimes . and it's price is also good. but the micro stuttering gives the card a bad reputation.and the power consumption is high
I won't spend on a 4870 x2 or a gtx 280 for sure if I'm not playing games in 1920*1200 resolution or above (28"or above) coz it is a real wastage of money,
(26' lcd is Rs. 80k+ and 28", 30"'s are like Rs. 150k

)
Best choice : HD 4870, GTX 260(cheapest) tie
2nd best choice : 9800 gx2
no third card as I dont like 4850 in cxfire
additional (AFAIK): 8800gt gives better frame rates in most big labeled games compared to 3870, refer reviews.
9800 gx2 is better than 8800gt in sli in most cases and both setups have micro stut problem while the gx2 stuttering delay is higher than the 8800gt sli.