I registered just to reply to this thread.
I'm a long time PC user, recently I got the urge to try OSX, so I bought myself an iBook G4 back in April. It was nice, but the aluminium "bling bling" got to me. So I sold it and got a Powerbook 12". That is a nice little machine, a flawed gem as they say. Crappy a$$ screen brings it down like the bastard stepchild it is.
After the escapade with the Powerbook I sold it and went PC only again for a few months till just last weekend.
I had the urge to buy a Mac again, so I was debating whether or not to get the new iMac G5 or 15" Powerbook. After going to the store and checking them out I went with the 17" iMac. I can't say this enough, the screen on the Powerbooks sucks...a lot. But the screen on the iMac is nice...very nice. 17" is perfect for the avg user without a lot of space. 20" is hot! But not $500 more for the same machine minus 3" and 80 gig hd hot.
Anyways, after using the iMac for 3-4 days I can say that I love it BUT it has problems:
1. Check the Apple support forums for the iMac G5. HUGE thread on noise issue due to fans. It's a really "whiney" sound. High frequency, ugh. I have to put it to sleep every night or else it really bugs me.
2. Ram. If you get the iMac, get ram. No, get A LOT of ram. OSX eats ram like a 5 year old eats ice cream. 512 should be the bare minimum here. Go with 2 x 512 for the 128 bit channel thingy. You need both the ram to be the same. I.E., buy it at the same time from say...Crucial.com
3. Fan. Ugh. Yes.
I like OSX, I also like Win Xp. I'm a part time gamer/full time engineering student so I keep my Thinkpad around. OSX can do almost every major thing you want it to compared to XP. BUT it's the little programs that will get to you. Programs lke Autocad (Ok it's not "little"), Solidworks, Pro/E...see a trend here?
At this point in time, I would not buy the Powerbook. They're due for an update in Janurary. Mac rumor sites are predicting a big update at MWSF in Jan 05. I would either get a iBook or iMac. And of course more ram.