>XFX 9800GT 1Gb Price 14,500
Inno3D 9800GT 1GB Price 11,000

These 2 will perform the same. Between the 2, get whichever is cheaper (inno3d -- plus, it comes with a free game).

>HIS IceQ 4 HD 4850 512MB Price 13,500
GTS 250 512MB Price 14,500

these 2 perform better than the 9800 GT's, but their performance goes head to head.
If you don't mind the lack of PhysX (Radeons use the Havok engine), go for the HIS 4850, otherwise, its a very small price to pay for the GTS 250.

Here is a list of games using Physx engines:
http://www.nzone.com/object/nzone_physxgames_home.html