I just "upgraded" my Prophet2 Pro to a GF3. Was it worth it?
Maybe.
The 2d is better, in my opinion.
Runs games faster, FSAA a lot faster.
Has some features upcoming games may/may not use.
I guess it depends on how long you're planning to keep the card, if you really want to upgrade now, and how much money you have. I think if I have the GF3 still in a year it will be a more viable card than the Pro.
BTW- since when is ~$300 too much for a leading edge VGA?! I paid that for my Voodoo1, my Voodoo2, my TNT1, etc.. The V5 was $300. at it's release and for a long time after, and when you compare what it brings to the table vs a GF3, it's kind of like comparing a BMW 9 series to a Yugo.