If you can save more money and wait a bit the 6200, 6600, and 6600GT AGP cards will be out soon. All are suppose to have great performance.
6200 retails $129, 6600 Im guessing $169, and 6600GT at $199. From reviews I read they are all suppose to be great cards and overclock well.
This website has some reviews on them you may want to read
Heck, the way I read the 6200 review, that little card will outperform my $200 dollar GFFX 5900! Not bad for $129