Sorry I didn't reply earlier koolj
With the X700...it's a 512mb card that's based on technology that had 256mb as max over a year and a half ago...bad idea IMHO
the 6600...same as above...but a bit newer.
the 7300 is the way to go i would say
it's newer, (being around 6-7 months old) and it's EVGA, which as i understand it, have an unlimited warranty...so you can do almost anything (except solder random capasitors and resistors onto the card) and still claim under warranty if it breaks....can you say overclocking? (I would double check this before you go doing anything with it first

)
out of those 3, that's what i would chose.