More Beginners Help, Which laptop should I buy? Options

[cully]

I hope someone can help me because I have spent too many hours looking at too much information, and my head hurts. I am simply buying a mac laptop for my boyfriend for his birthday - he is an electronic musician and that is the reason I am buying it, it is hard for an electronic musician to make music without a good laptop! I know he likes to use Digital Performer, Reaktor, I don't think he uses Pro Tools (though I do video/film making and I would love to use Pro Tools). I've done editing on G4 desktops that had at least 1 GHz CPU, but I haven't used the slower laptops and am not sure about the difference in CPU speeds. I am on a serious budget and have these options: G4 powerbook 500 MHz pretty used or G4 ibook 800 MHz pretty new. I have almost bought the powerbook, but I am worried about all this stuff I am reading about incompatibility with audio programs, etc. I will be maxing out the RAM (the powerbook has room for 1GHz, the ibook 640 MHz I believe) and getting an external Lacie drive. That is for sure. But which computer is faster/better? I don't see any serious musicians out there with ibooks. it's always powerbooks. If you made it through this rambling post, please help!

Also, if neither of these is good enough I could always bite the bullet and find an 867 MHz powerbook.

As a side note, how can you tell whether RAM is quality when you are buying it? Do you have to watch out for anything?

THANK YOU THANK YOU THANK YOU