^ No, not really. My friends 9800GT OC'd still plays games flawlessly. Games are not coded to be limited to current GPU's, the same way it is for GPU's not being made to only handle current games.
The only game the 9800GT struggled on was Crysis, and that game... A computer with 10 i7 CPU's and 10 5870's won't touch 100FPS. (figure of speach.)
There have only been 2 games in the past 3 years that I know off, that exceed todays current GPU's, and that was Crysis, and GTA IV. (GTAIV being terriblly ported.) Other then that, a GTS250 can handle 90% of games on high, without a doubt.