Just looking at some Computex links and saw a picture of this HD4650 AGP GPU. It may be a good option for older systems still using the AGP bus and probably not very demanding of power, about 30 (+ or-) watts and no additional feed from the PSU needed.
http://www.tweaktown.com/popImg.php?img=news_ctxgigabooth097.jpg
$99 at newegg
http://www.newegg.com/Product/Product.aspx?Item=N82E16814125281
http://www.tweaktown.com/popImg.php?img=news_ctxgigabooth097.jpg
$99 at newegg
http://www.newegg.com/Product/Product.aspx?Item=N82E16814125281