i have a ze5185 and its 'ok' i say in quotes, since the video card sucks chrome off a tailpipe. its a good business style laptop, works with a lot of older games, or topdown style games.
if its the same card, or lesser i'd skip it, if it were for games.
checkout the hp forums you'll see us all bitching and whining about how bad the graphics are
even during dvd playback
i'd hold off on an ibook at the moment, theres a new one coming out shortly, that will push down the price , i just returned my 700mhz ibook coz it had intermittent problems, some people have been complaining about common problems with them, i liked it while it worked though.
also ebay is a bad place imho for apple laptops, people frequently spend way over what the retail is on closeouts and such, i've seen g3 base ibooks selling for over the price of a g4 ibook recently. i bought my 700mhz g3 ibook for $519 from frys with a $69 2 year extended warranty. people are really unwilling to price them appropriately since they paid so much for them in the first place, and a lot of people are willing to overpay