Apple Warranty question

The general rule is that it is especially important for laptops. They are more prone to problems since they are moved around more. You have a year of coverage included. If you have many problems during that time, definetely get a warranty. On an iMac it's your call. On a laptop, definetely get it. After a year, you will pay lots of money if a repair is needed.

The "worth it/not" argument about AppleCare has been going on for some time. It's more useful on pro machines; I'd definitely get it if you're getting a MacBook Pro or Mac Pro. It's the user's preference on consumer Macs, but if anything drastic happens while you're covered, Apple will be there, and that's good to know.

Last/mid-rev G5 PowerMac owners who had their systems peter out on them generally received Mac Pros if the problem was not worth fixing, so you could end up with a better model if something horrible* happens to yours.

*TEF (Total Existence Failure) of Macs is a very improbable occurrence, but if you're worried (don't be, really), get AppleCare.