Upgrade today and maybe save some grief tomorrow.
By the way, people who own ATI video cards can now update their drivers automatically through Steam. I tested this feature some days ago with my 5870 and it works fine.
I tested this feature some days ago with my crossfire'd 4850s and it... didn't work at all
I let it sit a few days, let the keeners see if it has some silly fan-killing bug. After that nvidia thing this summer i'm paranoid.