I recently purchased a G5 Mac, the big aluminium boxy thing, not an iMac. Nice machine. Thoroughly obsolete, but still works fine and runs Ubuntu Linux rather well.

These machines are useful to people working on embedded Linux for big-endian targets -- far easier to debug code/drivers on a desktop machine (eg. G5 Mac) than on a teensy embedded platform with less advanced interfaces. The big boxy G5 even has PCIe slots.

Cheers