Wow so much hostility on this thread
We should have a sticky on which PPC to get, this queston has come up so many times, what about something like this :-
1. Space an issue? - Mac Mini or iMac (G4 because they are pretty and more relaible than G5 iMac's)
2. Space not an issue? - Then of course (would assume this is too obvious but then I keep seeing people say "A G4 will be enough") go with the fastest most up to date your budget can stretch to with the caveat that.....
2a. A liquid cooled Quad or Dual 2.7 could be problematic... but will give you the most 'bang' for your buck..
2b. A 2.3 Dual Core is a nice sweet spot for performance v reliability.
3. If you are not specifically after a PPC then go with an early Intel (budget allowing..) at least you can run current/more current software and it will inevitably last longer if you intend to do serious work on it.
Comments, don't worry - I have a thick skin and it's only a suggested list - Do think we should have a sticky on this though when it's 'agreed'