Well I have a PS2 and pc with Geforce 6600gt. Both have its advantage. The PS2 may cost u around 8K. The slim version may cost more. Remember these are gray market price and if u want to buy from Sony the price could be higher.
Again the game disk would cost from Rs.50-200 (gray market) depending upon the title and it popularity. But remember that some game titles are solely made for console or PC.
One big advantage PS2 will have that it hardware will never be outdated for its games. Meaning if ten years from now (which is unlikely possible) if a game is developed for PS2 it will run smoothly on it, without glitches. But for a pc u always have to upgrade in order to keep up with the development in graphics.
Moreover PS2 is slowly being phased out but there is a vast library of games to choose from which can keep u busy for a long time. One more thing is that slowly game developer will stop bringing out games for PS2. So latest games may not be available for it (but that situation is still quite a distance away). Reason being that PS3 is due to be lauched and SONY would want its new console to sell more than PS2.
So if gaming is ur sole purpose then buy a PS2 or even wait (if u have patience and money) for PS3. If u want and all-purpose machine with good gaming capablity then buy a g-card. For the budget equivalent to PS2 u could get a 6600gt 128 AGP/PCI-E.
As for me, I enjoy gaming both on PS2 (4 years old) and PC(upgraded 5 months earlier) equally.
Sorry for the long talk but tried to explain my point of view. Rest ur desicion.