I spend my days in screen, emacs, irssi, and various Mozilla apps. I'm pretty happy, but one that that drives me crazy is that C-a (i.e., CTRL+a) is "go to the start of the line" in emacs, and also how you invoke screen commands. So running emacs in screen means you lose C-a.
Not any longer. My current build and analysis cycle is close to an hour, so I have time to do things lower down on my TODO list, like read the man page for screen:
C-a C-a (other) Toggle to the window displayed previously. Note that this binding defaults to the command character typed twice, unless overridden. For instance, if you use the option "-e]x", this command becomes "]]".
C-a a (meta) Send the command character (C-a) to window. See escape command.
Happy day! Ted says he can't believe I don't know this, but it's one of a million things I have yet to learn.