Need Help Choosing A Video Card

Well, I'm finally going to buy a video card. I have a few choices to make and would like some help. I'm thinking of something top-end or close to top-end and need to know which one is the best idea.

I'm thinking of a 7950GX2, a X1900XTX, or a 7900GTX.

Of these, which one would be the best for the money. Since the release of the 7950s the other top end cards have dropped alot, and since DX10 isn't too far off I'm not sure if I want to spend 560+shipping on a card.

Both the x1900xtx and 7900GTX seem like they can run most modern games very good and should last for atleast until DX10 comes out, so my question is: Is there really any reason to go up to a 7950GX2 if I don't plan on playing my games at the very highest resolutions?

BONUS QUESTION:

I've done some research on N-Vidia vendors, and it seems they are pretty similiar, with BFG, EVGA, and XFX coming at the top of most peoples lists and with them all coming in at pretty similiar prices, however the ATI cards seem to vary ALOT more in terms of prices are their top manufacturers the same or different? Also does ATI make their own cards? I see alot of cards in boxes that don't appear to have manufacturers on them and was just wondering.

Actually I've been able to find x1900xtx for 400 or so, whereas the 7950GX2s are usually up around 550-575...

Well the price I'm looking at for the XTX is only 50 bucks more. At this price its a steal and I think I'll go with it and see how long it lasts me.

Yeah I pretty much made up my mind when I saw it for that price, considering its a 2 hundred buck difference between that and the 7950GX2 I think I'll just stick with the x1900xtx for now, by the time the power of the 7950GX2 really gets used it'll be about time to buy a DX10 card anyway and this'll give me an $200 to go above whatever I was going to spend then so it'll improve that one too.