Nooooooooooooooo... i would reccomend that before you buy either of them you wait until the GTX 260 Matrix is released. Apparently, according to legion hardware, it has massive overclocking potential and can even outperform a GTX 285. Best part is, it should be priced relative to all GTX 260's meaning that you could save a considerable amount :)
Personally, im waiting till the end of this year before i upgrade gfx, althought theres no confirmation, i have a feeling that the next series of gfx are gonna be released soon

. That and i haven't saved up enough