Good choice. The 7600GS is a solid card that actually offers very similar performance and features to that of my own 6800GT, but for less than half the price I paid last year.
There'd have been no point in getting anything much faster than a 7600GS as it would likely be CPU bound, and unable to be used in a new box due to being AGP.
One thing for sure is that a 7600GS will be one helluva jump up from the 5900 I believe you had.
By 
Good choice. The 7600GS is a solid card that actually offers very similar performance and features to that of my own 6800GT, but for less than half the price I paid last year.
There'd have been no point in getting anything much faster than a 7600GS as it would likely be CPU bound, and unable to be used in a new box due to being AGP.
One thing for sure is that a 7600GS will be one helluva jump up from the 5900 I believe you had.