dtach - this is a life saver whenever I get disconnected from the interwebs. It detaches a process from the controlling terminal.
dvtm - a tiling terminal manager. I used to use gnu screen but I prefer the layouts that dvtm offers. This plus dtach replaces 99% of what I used screen for.
Vim - my text editor of choice.
pyclewn - integrates gdb with vim nicely.