If I may add to the above list
GPE Calendar: Works and installs seamlessly
GPE Todo: To do task List Install
GPE Summary: Keeps an updated summary of appointments and todo tasks that you can interact with on the desktop. Install
XChat: Beautiful IRC client. Install
easy debian with open office 2.4, but that installation is not as seamless. I would suggest this though if you're willing to attempt it. There are plenty of instructions for how to on this forum.
Xournal: Note taking program, you can also open pdf pages and take notes onto them with your stylus. Install
AlmostTI: Emulator of full Ti-83, 85, 86 Calculators, Love this thing basically my N800 is alsoa full graphing calculator! Install

Plus there is a multitude of widgets that you can use based on what you need.
On top of the launchers that corrupt listed, I use
omweather - shows weather, if using gps and connected to internet will autoupdate location and weather data.
Homediskfree - shows disk space available
LoadApplet - this applet is great because if something hangs you can just look at the list and kill the process without having to use the terminal

All these things except for easydebian require basically no tinkering, simply install from extras-devel repositories... very easy.