GNU Screen. My Personal Reference.
At my PC, I usually multi-task by having many terminal windows open. This is great, but on a terminal (see my last post about the VT420) it is not quite so convenient. Fortunately, GNU Screen has come to the rescue. I typically only use GNU Screen for running my jobs in the background on servers after disconnecting.
Since I use GNU Emacs, having C-a bound as an escape key is very annoying. I basically don't use C-o, so I have bound Screen's escape key to that by setting "escape \Oo" in ~/.screenrc.
The most convenient way for me to switch between tasks now is to use C-o n and C-o p for next and previous sessions, respectively. Sessions can be created with C-o c and renamed with C-o S-a. A menu can be produced with C-o dquote.