How to roll back Ubuntu to a previous version?
I really don't like 11.04.
Is there any way to revert back to 10.10?
If it's the GUI that you don't like about 11.04, then you can just revert to the classic GNOME interface (instead of the new Unity interface), rather than downgrading.
To do that, before you enter your password on the login screen, select 'Ubuntu Classic' as the session type.