It's sad I can't use the newer drivers due to a bug that's been there since driver version 2.12 (found in Ubuntu 10.10). I need MS Office to work under Wine, since LibreOffice still can't do some thins I need (like full compatibility with Office 2007 documents), and any driver newer than 2.11 causes major rendering errors (black areas and borders).
It also affects other programs, as we can see by the bugzilla entry at freedesktop.org:
https://bugs.freedesktop.org/show_bug.cgi?id=30157
I even downgraded the entire Ubuntu to 10.04 because of another problem with my trackpad too (it takes 3 to 4 taps, sometimes, for it to register the click).