I must stay that recent beta versions of FF 4 (esp. 8-10) have been a lot better, have been compatible with my add-ons and pulling me back towards FF (used FF from 2005-09 but shifted to Chrome in 2010/win 7). Chrome may be 10 in beta versions but that is just a marketing. In my usage, Chrome is getting worse in their zeal to release updates every week, and their main USP-minimal interface, clean look, better UI-is now in FF. I see myself switching increasingly back to FF (usage of FF up from say 10% in late-2010 to almost 100% over the last month).
As to NVIDIA as a side note, the numbers (in version terms) may be going up, but I have not seen a stable version after 258.96.