Love the Powerbook, but there are two things that are constantly annoying.
1) The latch is worthless. It's like a cruel joke. You push it down, think the machine is closed, then it pops back open a second later. Always pops open in my carrying case. I'll be in class or on the subway, and I'll hear my Entourage reminder "ding" from inside the bag. I miss the old G3 Powerbook -- now that was a latch.
2) The A/C adaptor. I'm on my fourth. Eventually, the connector stops making the connection despite twisting, coaxing, and manipulating. Fortunately, Apple care covers it.
Great machine, but some of the little details are lacking.