I just finished my first year of college with my MBP so I hope I can offer some guidance. I absolutely love my MBP. I personally feel that the white macbook is quite feminine, so I would try to stay away from that (sorry to all the males with the white MB). Not to mention the white MB trackpad and palm rest turns kinda nasty after awhile. My brother is going to UF in the fall and will probably be getting the blackbook for that simple reason.
As far as screen size goes, I think the 15in. is much better for writing on, although I do have a 42in. plasma I hook up to that makes it even better! Writing is made much easier when I am in the library with the 15in compared to my friends 13in MB. Also, you do not have to tilt your head down so far with certain desks that are low. A major bonus because the desks at my library are really low.
Weight is not a problem with the MBP, especially if you are not moving it around very much. I personally like to take notes by hand because I learn better that way and I am not distracted by AIM or Facebook. Although there are some classes where those are a necessity to get through the lecture.
To answer your question, I would wait. Like others have mentioned on here, you can get a free iPod and a decent printer for free. The MBP is much more powerful than what I need it for, but there is something about the prestige and look of having one. Please correct me if I am wrong, but I have seen multiple rumors suggesting that Apple is going to do a complete revision soon due to the new chipset required, perhaps near the begging of the school year, end of summer area after the iPhone dust settles. There is no harm in waiting 2-3 months.
I am pretty computer savvy myself and picked up OS X fully in about 2 days. It was hard to drag me away from the computer in those two days because I was in love lol, but it really took no time at all.
edit: I have had to have Apple replace my HDD in the first month and just had them replace my battery. Bad luck or typical? Your call. I also plan on keeping mine for awhile unless Apple does something drastic with their touch interface that I like. Bring on iPhone v2!