My wife used to use a Mac G4 iBook; we bought it about five years ago. It's been through two hard drive replacements, one it-might-catch-fire-so-it's-free battery replacement, one it-might-catch-fire-so-suck-it power adapter upgrade, and one OS-and-app upgrade. (This is the first time I've paid for an OS where it hurt. We lost the install disk for Panther or Mud Leopard or whatever it was, and had to buy a replacement plus a copy of iLife.) (I've also bought Slackware 96, as part of the Slackware Bible; Slackware 7, when I was amazed to see it at Chapters and figured I should support their sudden smart thinking; and OpenBSD.)
Finally, the hard drive (I think) started failing again, and we'd had enough. I'm not sure what The Right Thing To Do(tm) is for figuring out when to replace vs. when to invest in upgrades, but I'm starting to think that half its replacement cost is about right. And that's what we were up to, not least because it's a damn Mac and if you were meant to open up the case your name would be Cthulhu Morlock instead of John Doe Eloi and it turns out the Morlocks charge a lot (deservedly so, what with avoiding the sunlight and all) to do things like spend twelve hours with a team of four opening up your iBook to replace a hard drive.
So we got a Dell. My parents visited recently with their new Inspiron 13, and I installed Ubuntu on it and was surprised that a) everything worked except maybe suspend and b) holy CRAP it's easy to install Ubuntu beside Windows these days. The form factor was nice, the specs are wonderful (thank you, Vista, for making notebook specs so nice, as someone else said), so that was that.
I settled on an Inspiron 14 as it was slightly cheaper and almost the same size and seemed like it would do the trick. I came home early from work yesterday, picked it up and while Clara took the kids out shopping I wiped Vista and threw on Ubuntu (Jaunty). The hardest part was when I insisted on setting up partitions (I can see the reasons for One Bigass Partition but I'll be damned if I'll like it); that GUI is just awkward. But it was only once and it all worked.
After that, I installed Cheese for the webcam, Thunderbird for email (damn Evolution! damn it to hell, I say!), flash, set up an account for myself, ran updates and...that was it. Even suspend seems to work. Hell, at this point I can't even remember who made the wireless card; it was probably Broadcom but I didn't notice any restricted driver warning so maybe not.
It's a nice machine, if a bit large for my tastes and a bit cheap-looking. But for the price I can't complain.