Go with the ibook and add a 512 stick of RAM --- I am running the 500 mhz model with 640 megs and a 40 gig travel star 5400 rpm 8 megs cache HD and I love it !! Runs awesome with no issues .. I use allot of picture/photo utilities and simple editing, you'll never know the difference.
Dual 1.25 with a gig o' ram - 2x120 gig drive2, 30 gig, 120 USB 2 drive, superdrive and a 52x USB 2 CDRW 19' Samsung 19' monitor - OSX 10.4.1
B&W G3 400mhz ATA 66 card with two 30 gig drives, 1 gig of ram and a ATI radeon 7000 - OS9 and OSX 10.4.1
ibook 500mhz (Dual USB) 640 ram - OS9 and OSX 10.4.1
acidtuch10 - email = firstname.lastname@example.org