Power PC 5500
Yeah, I got one of these.
There easy to upgrade. I swapped a mainboard from a 6500 that had a 300MHz CPU soldered onto it and stuck it in mine. The RAM can be upgraded to 128MB (2 x 64MB) but I only got 64MB (2 x 32MB) in mine.
I stuck a 80GB ATA133 hard drive in mine also and got it dual booting Linux. I think the largest capacity hard drive they can take is a 120GB.
I also stuck a PCI network card in it.
The 33.6Kbps modem makes a good hands free telephone using the built in speakers and microphone and of course the TV with it's teletext is neat.
On the downside, the TV and modem don't work under Linux and I haven't got the Network card to work under Mac OS.
It's going on ebay soon. 😱