Based on the specs, it sounds like the exact model I have, and it is the first revision of the 15 inch aluminum design. So, possible flaws, and their fixes:

1. White spots on the screen. This revison was affected nearly universally in the begining, due to the position of LCD screen spacers on the back between the LCD and aluminum cover. I still have a background somewhere that circles the exact spots they will appear in. For me, it took two months of carying it around for them to start to show up. Apple fixes this free of charge, and if you get a good service center, they can do the repair in store in 20 minutes. If the Powerbook was bought after January 2004, it is not likely to have this issue.

2. Dangerous battery. This affected batteries sold January 2004-August 2004, and only certain ones. To identify them, go here. If you are affected, Apple ships you a new battery at no charge.

3. Latch issue. As commented by others, you may notice the latch doesn't keep the lid closed. My unit did this after two weeks notice. Fix was to catch the latch before it hid in the lid, and bend it down a smidge. Problem has never occured again of the latch not staying shut.

I'm not sure about the ram issue, this was the first I heard of it, so it may not be an issue on your model.