My second ever PPC Mac was an iBook G4 1.2GHZ I acquired off Ebay for $40 in November of 2012. It just needed a hard drive replacement, and it was ready to go!
I upgraded the RAM to 768MB, and pretty much left it that way. It ran pretty well on Leopard, but I wiped the hard drive nearly every other week because I like things tidy, plus I'm weird!
I loved that thing, and it was my primary laptop for a long time. About a month later though, I noticed that it would no longer take any battery power, but it would charge the battery. I finding that I would have to replace the logic board, I ordered a new one. It was getting costly to keep this machine, so I later sold it for $60.
This started a phase of mine where I bought and sold many iBooks. Later on, I had to stop because I was starting to save up for a more modern computer, which I later purchased and it was my Black Mid-2007 MacBook (SMEXY), my first Intel Mac EVER.
I wish I had a G4 laptop, it would make an excellent addition to my 2-month old MacBook Air!