I recently got back into Android programming and came across a problem that caused me to burn a lot of hours, so I figured I would post it here to help out.
Basically, whenever I would run any Android emulator in Ubuntu (x64 or x86, 11.04 or 11.10, but likely others as well) the emulator would just hang. Most posts on the topic said “wait longer” because it was just trying to start up for the first time. In my case however, it had to do with the fact that I had “3D Acceleration” checked in my VirtualBox settings. Simply unchecking this box allowed the emulator to run correctly.