The new age graphic cards are used for two major applications :
1. Graphics processing for games and otherwise
2. Used as a General Purpose GPU for parallel application acceleration through the new technology CUDA.

I will be covering the performance of 9800gtx in both these fields.
1. Graphics for games : a) As a G92 architecture this card gives a very decent performance for most of the current top-notch games. With a great texture fill rate and 128 stream cores it packs with it the power that most high end gamers demand today. At a price of around 300$ its a good value for money. I have personally experienced the power through games like Prince of Persia 4, STALKER and Call of Duty4. You can run all these games with high graphics settings - like Vsync and Full screen Anti Aliasing and still the fps achieved is a whooping 50-70. Apart from the high performance the card comes with a nice big fan so there is no heat problem even in hot regions like india. It supports nice overclocking for the enthusiasts and also 3 way SLI which is plus and can be very help full in long run as you can keep on adding more of these babies instead of buying newer and more costlier cards.

2. For CUDA developers : The card has become a standard development platform for developers as it has enough power and supports latest version of CUDA. Compute capability is 1.1 but still you can get nice performance speed-ups.

Thus I think this card is here to stay for a long time.