Since I upgraded to Oneiric, the top left Unity menu button is missing, fonts look a bit weird (font size changed) and the login screen looks like the one from Natty, except with a GTK1-like gray theme. Apart from that, everything (e.g. the Unity launcher bar) looks kind of okay. I have no idea how to pinpoint the problem, are there any log files I should check? Xorg.0.log doesn't contain any errors.

I have a Lenovo T410 with a nvidia graphics card and the proprietary driver is installed. Hardware acceleration works fine.