1. You need no understanding of UNIX/BSD to be incredibly productive on OS X.

2. Wait to buy for a couple months, the next release of OS X (10.4) is imminent.

3. Buy the 'Missing Manual' for the version you get.

4. Run through [link|http://www.atomiclearning.com/macosxpanther|these] free tutorials. In fact, do this now, it will answer a lot of your questions.

I'd say for you, get an iBook. Given your past postings, and your current '98-lite' system, the additional features of the powerbook will mean little to you.

Good luck!