Now is probably the best time to buy a new powerbook. A revision may be coming out sometime in early 2005, but it is generally a bad idea to buy first-generation laptops from Apple. The G4 powerbooks, for example, had a lot of problems that have since been worked out. So you will probably be waiting at least another year if you want a stable and reliabile G5 powerbook.
Also, the 12 inch G4 is a beautiful machine. The price is low enough now that, with your student discount, you can get a 12 inch PB and an iPod (with the cram and jam deal) for about $1400. Oh, yeah, you said you're a student? If you buy now, you'll also qualify for Cram and Jam.
The G4 powerbooks have been revised and refined, as well as undergone some price changes. Now they are perfectly ripe for the buying.
As for features, what exactly is your budget?