I personally picked up a bargain Powerbook, £700, off Ebay recently...plonked 2GB and i am very happy with it. For the next 7/8 months it will replace my iMac G5 as i need portability.
Personally what is better about pbook imo:
-Cooler, but not by that much..
-Very long battery life - more than 3.5 hours doing a fair amount of work
-FW 800 - but i guess irrelevant for ur wife
-Noticeably quicker dvd-writer drive, 4x just takes too damn long
-Ability to have a isight does give more felxibility
-Fast enough to do everything you ask and more
-PPC is here to stay, all those people fretting about it being outdated, well it won't for the next 3-4 years, and by then i am sure you will want to upgrade your machine.
-Runs perfectly, rev e or something and pretty much no issues.
Cons of the pb:
-No isight built in, i personally would prefer this than getting a seperate one
-Brighter screen, i love bright screens - the pb one is nice, get high res version, but it definately is noticeably duller.
-Obviously gonna be slower, and a lot slower. Those mbp's are blazing fast but you only notice when pushing them (doubt ur wife will notice)
-No remote - but i think this is trivial, front row is nice but i am using it less on my imac, and i don't think many people will use it on a 15" screen. Also there are alternate ways to get it.
So basically i say go Powerbook, they are gorgeous, half the price but they are definately not half the laptop. I really like mine and i guess i will sell when i see a improved mbp.