I just switched to LXDE from Unity, and I can't tell you how please I am with the performance!
The fact that I can configure this clock applet to any format that pleases me is a big deal to me. In GNOME and Unity, you can't even show the year:https://bugs.launchpad.net/ubuntu/+source/gnome-panel/+bug/465689
Now, here in LXDE, I have my clock display set to:
%m/%d/%Y %l:%M %p
07/12/2012 1:49 PM
Perfect for me!