At this point, I will be graduating from college in a few months, so I have yet to purchase home owners insurance. However, very valid point about desktops. Almost anything can be swapped out from an OEM, unlike a laptop.

Yes, get it
 

Here's the deal: if you have accidental damage to a portable, it's going to be expensive to fix. If you contact Apple directly or go to an Apple Store, you're going to have to do a mail-in repair and pay a "tiered" flat rate. Assuming they don't need to replace any drives: just case parts ("plastics", even though they may be metal) and maybe cheap parts like the DC In board where the AC adapter plugs in, you're probably looking at about $400. What's kinda nice about these tiered repairs is that they replace anything with any evidence of damage, like a broken corner on a circuit board. Unfortunately, if you need something like the optical drive or logic board replaced you're looking at even more money.

Now, if you take it an Apple Authorized Service Provider, they are free to do the repair in-house if you want and charge you for parts and labor. With a 12" PowerBook, you're looking at a lot of labor, though the parts might not be too much.

Anyway, regardless of how you take care of the current problem, GET APPLECARE!!! Apple charges a flat rate for mail-in repairs that do not involve accidental damage, no matter what needs replacing. For PowerBooks, it's currently about $325. AppleCare pays for itself with only 1 repair. And if you have 2, well, you've saved $300.

In the end, it's like any insurance. If you can afford to take your chances, odds are in the very end you'll come out ahead if you never buy any insurance (otherwise the insurance companies wouldn't make money). However, if you are not in a position to pony up $300+ dollars at a moment's notice because your PowerBook needs to be repaired, insurance provides you with a known price to avoid that uncertainty.

Personally, I'm sold on AppleCare, and I'm the type of person who NEVER buys extended warranties.

A friend had a solder joint fail on his iBook power connector (probably due to repeated flexing; it was one of those iBooks :) ). Apple sent him a prepaid shipping box the next morning, and 24 hours later he had a new (repaired? don't remember) iBook.

My Quicksilver DP G4 started flaking out, throwing kernel panics. It got worse and worse; by the time I was able to get all my files backed up it was nearly dead. The local Apple store replaced the dual CPU module(s) for free; their out-of-warranty cost was something like $800.

Either one of these incidents would have justified the cost; both machines were well beyond the standard warranty period. YMMV, but when I order my new G5 I will definitely buy AppleCare.