Maybe I'm missing something, but the 1950XT isn't a DX10 card.......right now there are only 2 on the market: 8800GTS and 8800GTX. I'm assuming you're getting one of those now?
As for affordable OC'ing mobo, can't go wrong with the Gigabyte S3, it'll let you hit 3.0 ghz no problem with an E6300 and that Corsair, at less than stock vCore
There are some ASUS boards that are recommended as well. Check out the TH mobo shootout article, some good stuff there for recommendations.