I'm getting one of them, but other than size and price I see no difference.
Someone obviously forgot to look at the technical information. I don't think they make those 2 anymore though, do you mean the MacBook and MacBook Pro?
Neither are made anymore mate.
iBooks were replaced by the MacBook.
PowerBooks replaced by the MacBook Pro.
Each are faster, lighter, slimmer, and far more powerful than the one that came before them. The Pros start at $2,000, but you will need another 512MB stick of RAM to game on, so make it about $2,100. Judging by your lack of knowledge on how to research things on the internet, I'm going to venture a guess and say you are not old enough to have a job. So I'd say that the MacBook fits you best.
1985, apparently. Realistically for someone who doesn't have a job, the cheapest Dell available would be best. I assume if he's asking the question he has enough money...assuming he's bothered to check prices.
MacBook Pro is best, but also it depends on your price range.
You could probably get an iBook or PowerBook from eBay or somewhere similar, but TBH I wouldn't bother. I have an old PowerBook G4, and they're nothing too special
I would save up for a MacBook if I were you.