I got my HP a520 Pavilion computer in May of 2004, and used nothing but Linux on it. Eventually, the fan gasped, memory chips were dying, and using it was getting painful. So I upgraded it for Christmas. I am now running a little System76 desktop machine, 2 gigs of RAM, prebundled with Ubuntu 10.10, "Maverick Meerkat." It's a 64 bit machine, but I can't say as it feels blindingly fast. Much faster than the old HP, for sure. It cost under $400, and will probably last me another 6 years.
It didn't take long to set up. It found monitor and printer with no problem - no setup necessary. I was stumped for a bit until I realized that what I thought was a flash drive was in fact the wireless modem. Nifty. The work of maybe half an hour to grab all my other programs, set things up for multimedia.
I fiddled around with Evolution (Outlook for Linux) for an unnecessary period of time, trying to get it to use my Google contacts and calendar. The trick seemed to be to start the program, then quit, then start it again. After that, it suddenly knew that when I asked for a new calendar, to offer Google as a type. Same thing with contacts. That stuff always feels so sloppy to me. It should work the first time. I also played around with reading in some older Thunderbird folders. So far, so good. It doesn't talk with our Exchange Server - which seems a little too new for Evolution to know about.
I think I also had a little moment of confusion after I copied over my files. I had to issue something like "chmod 760 * -R" to restore my permissions. But that's one command.
On the whole, pretty uneventful. It makes life so much easier not to have to sync my Palm, but let the Palm Pre sync wirelessly with the cloud. And since then, I've updated my website (I got a book with a chapter I contributed on community reference), sent out a column, updated a few journals, and so on. A piece of cake.