Yeah, you should be all set with that card. The amount of memory (256MB) is standard for a "good" card right now, and the 256-bit interface is good as well. Overall, you should be set for awhile with this card before you have to think about upgrading. (raw guess, 2-3 years...)
P.S. I have a GeForce MX400, so I know your pain, man...
EDIT:
had a MX400. But now I have a GeForce 6600, and all's good