I just went for the latest WHQL (280.26)... but now that you've posted that I may as well give the beta's a shot - looks like there are some decent performance boosts!
Ah yeah the new BETAs are supposed to be good, they haven't caused me any issues yet... but i'm still waiting for the mythical drivers that NV keep hinting at, the new 300.XX series.
That's three of us in the 560 club then, lol. I'm also using the 280.26 drivers.
I've mentioned before my old machine wouldn't play Black Ops Multiplayer smoothly. Well the new machine does
And very good it is too I think, much better than MW2 MP imo. Just played a few maps and didn't do too bad really, considering I didn't know the maps and am just starting (no perks yet).
One snag - I noticed I don't have some of the maps and the map packs cost money. This irritates the hell outta me.