Your better choices in motherboards would be Asus and Gigabyte. The 975x chipset is the one to go with. But if you want to OC then Asus and Gigabyte with the 975x chipset are the way to go.
I like your PSU selection. It'a a very good PSU. I've had mine for about 3 months.
glad to hear that because i'm also going to buy that PSU
go for an asus mobo with the 975x chipset if you want to overclock
and i think the x1950pro 512mb has only a marginal performance increase compared to the 256mb version, so spare your money for something else