the GeForce 6 serias has no pro, either vnilla or Ultra, & GT
I would say really go for a 6800 nU, 10% less performance then GT & belive me U can play any game for the next 2.5 years at 1024X768 with 85 Hz & 2XQ AA & AX Anis, remember no matter how much better Card U get U can never play more then your refresh rate of your monitor & usuall they don't go higher then 100HZ for a 17" Monitor which is the norm these days & LCD are still costly unless U decide to give up 17" CRT for a 15 LCD
It is available in AGP8X, so U can easily, then 6800 nU from MSI for 18k, is a really good product for india, as it holds up for 2.5 years more to come, U will need to chage your gfx card only after longhorn, cos with longhorn the next DriectX will come, so before that for 2+ years games will be made in SM3.0 or DirectX9 & OpeGL 2.0
A GT over a 6800nU is not recomended here in India, reason, u can play just about any game U can on a 6800nU as U can play on 6800GT, but Y pay 6k more when it makes difference only in benchmarking
as long as all the games are playing smooth stick with your card, over a 6800nU the GT provides only performance, but U won't miss it with 6800nU either, U will get reasonable performance even with 6899Nu for nest 2.5 years