If you move your user profile off of your c:\ drive (in Windows 7 x64 in my case), Eclipse will no longer be able to start the Android emulator (AVD). It gives the following error message in the console:
PANIC: Could not open: C:\Users\dave\.android/avd/myAVD.ini
This issue has been documented here, and also a few solutions. The solution that worked for me was to make a symbolic link on the command line to the directory that actually contains the AVD settings:
mklink /J "C:\Users\dave\.android" "D:\users\dave\.android"
Now when Eclipse asks for C:\Users\dave\.android it is redirected to D:\Users\dave\.android where this directory actually exists.