This weekend I've been playing with an old IBM ThinkPad 600X. It has 300Mb of ram, 12G hard disk, 450Mhz Pentium 3 processor, dead li-ion battery and no built-in ethernet or wireless.
My goal is a machine for use on ham radio, most likely running one of the psk31 software packages. I'd also like to be able to use a web browser and check imap email.
There are some very tiny linux distributions around but I figured I'd like something fairly rich so I've been playing with xubuntu which can run in 128Mb of ram. My approach was to use the Ubuntu 7.10 (release candidate) alternative install - as the live CD wouldn't install and then install xubuntu-desktop as explained here.
The normal Ubuntu desktop, Gnome, eats 250Mb before you start up any extra applications. Xfce, used in Xubuntu, eats 244Mb so I don't see much benefit in not running gnome. (I must be missing something here...)
The show stopper has been sound. Sound out works fine, sound in doesn't seem to function. I can see lots of other folks running old hardware with the same problem. I'm using a Lucent PCMCIA wireless card that Ralph kindly sent me. (It actually has an antenna socket on it!). This was detected just fine and works really well. Ubuntu seems to be lacking some user interface for seeing wireless networks though.
Bottom line: A 450Mhz legacy laptop is perfectly usable with Ubuntu. Firefox is everything I want (with a plugin it even plays YouTube videos reasonably), OpenOffice is great and just gets better every month, Evolution email is fantastic, and the overall desktop experience is really solid.
If I wasn't addicted to MacOS and hanging out for Leopard, I could use this desktop every day.
Oh, and I really hate that little IBM nipple mouse thing. Trackpads are much better.
Cleaned the very dusty case up with eucalyptus oil which can dissolve all the sticky gunk under the silly "made for windows 98" and "Intel inside" stickers.