Resource Utilization: Ubuntu 10.04 vs 12.04
"I was going to suggest XFCE. If it's good enough for a pissed off Linus Torvalds, then it's good enough for you. Or you could try LXDE actually. I mean, you would have to put real effort into going on Ebay, and really search and hunt for a computer low powered enough that LXDE won't work. I mean LXDE is light, and good looking too. With the Ambiance and Radiance themes, it really does look as good as Gnome 2."
"How to run Ubuntu 12.04/10 or 10.04/10 on old computers with (very) limited resources"
Lightweight Web Browsers
Lightweight Chat Clients
Configuration: - Add Google Talk and Facebook accounts - uncheck: Buddies > Show > Buddy Details - Buddies > Sort Buddies > By Status - Tools > Preferences - Placement: Left - Close conversations with the escape key - Log all status changes to system log - Mute sounds - Idle 10 minutes - Available at startup - no smiley theme - Tools > Plugins - uncheck: Libnotify popups - psychic mode - I'dle Mak'er - Contact Availability Prediction