I vote for screen personally.
Screen is for terminals what window managers are for X. You can have multiple virtual terminals on a single terminal to make multi tasking easier... Think of a stack of papers one on top of each other and you switch between the pages with ctrl-A plus another button key combinations... You can also divide up Screen's "screen" in half, 3rds, or fourths to have mutliple terminals displayed at the same time.
The best part is that if you get disconnected (say you turn off putty, or your connection gets dropped) screen still sits there plugging away with all your stuff running just like you were there looking at it, until you log on again and do a "screen -r" to get all your stuff back. (of course if your ssh/terminal server reboots you lose the session.)