[Xion]

iTerm2 has few other fancy features, like horizontal and vertical splitting or Guake-like top-down terminal [0].

[0] http://ivanvillareal.com/osx/setup-iterm2-to-behave-like-gua...

[niggler]

I've used visor/simbl in leopard and snow leopard for years to get the top-down effect in terminal: http://visor.binaryage.com/

[haar]

Multi-pane input via cmd-shift-i, and saved pane/window configurations through cmd-shift-s and cmd-shift-r also come in handy.