Yes! I'm a MAC! I own an iBook... and it runs Linux (besides MacOS X).
Here are its specs:
I bought this laptop on secondhand in august 2004 because it was small, could run linux and was the only laptop that could easily sleep in Linux, at least at that time. The maximum time I managed to leave it in sleep mode was a full week, while on battery power.
The other reasons were related to the architecture:
This last one allowed me to learn how to write kernel modules and modify the source of lm-sensors module adm1031 and how to make patches. It also taught me that Apple engineers were not very clever when they designed the iBook Dual USB (late 2001) because they placed the graphics chip under the hard drive. The heat generated by the hard drive (which is a lot) will join the heat produced by the ATI chip and after some time the chip will fail.
Some people are claiming that they fixed their broken iBooks just by pressing the ATI chip against the PCB, which could mean the problem with the extreme heat is related to the solder joints of the graphics chip on the PCB.
Just one more thing, don't forget to check every now and then the new Apple Get a Mac ads!