Any true hacker knows that GUIs are just another way to have lots of terminals readily available.
If you do a lot of command line work, you probably have a lot of terminals open on your display at any one time. Terminator is a Gnome application that lets you run multiple terminals in one window. I've just started using it, and find it very useful already.
Using a grid layout means you can see multiple terminals simultaneously, unlike Gnome's terminal with tabs.
Other than the fact that it will eat some keystrokes, the ones it uses for run-time configuration and operation, it appears to be quite transparent. I can fire up Terminator, ssh into another machine, and then run screen. Or I can run Emacs as an X client. An excellent product.
It is very flexible. You can launch it with some command line options or set up a configuration file with one or more profiles. Here's my first go at a config file.
# This is a comment. Time-stamp: <2010-10-10 10:28:56 ccurley config> [global_config] focus = system window_state = maximise borderless = true close_button_on_tab = false [profiles] [[default]] audible_bell = true visible_bell = true background_type = transparent background_darkness = .7