Just make sure you get her an intel mac.
IMO the current intel iMacs are awesome value. I'd get one of those personally:
http://store.apple.com/Apple/WebObje...ECBF&nclm=iMac
You may also wanna check out the Apple refurb store for some bargains:
http://store.apple.com/Apple/WebObje...nclm=Certified
If you buy any current iMac or Macbook, they'll be way faster than here current G4.