You're not doing your body any favors if you use a laptop more than an hour or so a day. Desktops, or if you're pressed for space mini PCs, provide much better ergonomics. You could also outfit your laptop with a stand and separate keyboard to get similar ergonomic improvements.
Many of you use a laptop because you want to save space, not because you want a portable computer. It's not so tidy though if you want to use an LCD monitor and/or an external keyboard with your laptop. There are alternatives, for example, computer-in-a keyboard or computer-in-a-monitor. Several companies produce them these days. Here's a good examples of both. Another nice thing -- you won't have any laptop battery fires. :-)
Green PC: How to dispose of unwanted tech equipment without hassles, and where to find great new environmentally friendly gear. --Jamais Cascio, PC World
Dell has partnered with Goodwill Industries to recycle PCs and other unwanted electronics. The operation is called RECONNECT They are only active in a few locations today (Feb. 2007), but expect to see more as they get underway.
ObsoletePC.org is a little laptop centric, but they have some good ideas about recycling PCs too.Ubuntu and Kubuntu (the variant I use) have emerged as very useable Linux "distributions". They're suitable for computer users who have a little sense of adventure. I turned an old 0.3 Ghz (compare to 3.0 Ghz) eMachine that has a 2.1 GB hard drive into a Kubuntu computer that I use exclusively for business transactions because it's much more secure than Windows. :-)
The Ubuntu story is very interesting. An editorial in Free Software Magazine puts it succinctly:
"Then, a very smart man called Mark Shuttleworth made 500 million dollars in the .com boom, learned Russian from scratch, went to space, came back in one piece, funded several charities focusing [sic] on South Africa, and... oh yes, he created Ubuntu Linux."
There are dozens, actually hundreds, of Linux "distributions" -- essentially branches of the core Linux operating system. The nice thing is you can try as many as you like for free. Learn at LinuxLinks.com about which ones (other than Ubuntu/Kubuntu) you might want to explore. One interesting thing is that most Linux distributions come with *tons* of free programs for you to use.
Dan Martin wrote a revealing comparison of the differences between Linux and Windows. By the way, if you're not sure how to pronounce Linux, listen to Linus Torvalds say "Linux" himself.
Karbosguide: an "online magazine" that has well organized and easy to understand articles about all aspects of computers, including how they work, and how to do things with your computer.
Microsoft has *tons* of computer information online. There is so much there that it's tough for them to keep it organized, and tough to find it all. Here are some interesting places to go.
http://www.microsoft.com/WindowsXP/experiences/default.asp -- "Do Amazing Things with Windows XP"
http://www.microsoft.com/canada/home/ -- "Microsoft Home Magazine"