There were only a few issues that were pretty easily fixed, and I may, just may, have fixed the hanging on boot problem I had with version 10.04.
One problem I had was the Hard drive temperature reporting in Conky - it stopped displaying a temperature. This was because the hddtemp command could only be run as root - Conky doesn't run with those privileges, and I didn't want to start doing so. A quick search revealed a single line command to allow hddtemp to be run as a regular user:
sudo chmod u+s /usr/sbin/hddtemp
After doing that, the disk temperature re-appeared and all was good.
Fixing the boot screen
This was a problem that I had in the previous version, 10.04, as well as in 10.10. It is to do with running the Nvidia proprietary drivers, and switching to different video modes. Basically, there are some steps to try at this site, which I did. It involves setting some video modes in the boot loader. I initially tried 1680x1050 (about the best that was supported by my card, even though it runs at 1920x1080 once at the desktop) and got a comically large ubuntu logo during boot. A later change to 1280x1024 yielded a much better result.
So far, the boot and shutdown screens look much better, and I haven't yet had it hang on me. I am hesitant to call it truly fixed until a few more weeks have passed.
Edit January 7, 2011: If you do these changes and then switch back to the open source driver (nouveau), you have to undo the changes to be able to set the proper resolution for your screen(s).