The difference between the two machines - MacBook and MacBookPro is pretty much zero - mrmacfixit is right... BUT, there are some choices in application capabilities you need to look into - also, how you make the music you are recording will push some other decisions.
1) Apple bundles GarageBand. It is pretty solid. You can manipulate MP3s, connect midi instruments. For bundled software it is quite capable. Multi-track, panning, all sorts of plug-in effects and instruments. Export to iTunes or MP3...
2) There is some Open Source stuff out there - Audacity is one I have used. For the free download, you can't beat the price. It can deal with a lot of different sound formats, too. Very cool. I am pretty sure there are others - I just have no personal experience with them.
3) A lot of the pro audio engineers I know use ProTools by DigiDesign. It is Expensive, and I *think* requires their version on an interface between the mixer and the computer, but it is REALLY flexible and geared toward the pro end of the spectrum and multi-track recording requirements.
If "your music" is just you - guitar or keyboard or whatever... then the first two will likely be all you need. If "your music" means a multi-track pro-grade requirement, then the third choice is there for you.
The REAL decision you need to make - in my opinion - is not the laptop to get, but rather the method to get "your music" into the Mac. If you are using normal, analog instruments, then you have microphone, pick-up and mixer decisions that will have a much larger impact on "the best quality possible" than the computer hardware, operating system and audio application you choose.
Mackie makes great mixing boards... the Onyx 1220 (with optional FireWire card) is a cool little rig.
The type of music you are recording, where you are recording it and what instruments you use will dictate the types of microphones you might use. I don't think *any* mic built-in to *any* laptop will allow your "best quality possible"... Same with any mic that uses the 1/8" mic input on the computer.
Live-performance mics are very different from studio mics. A mic for a violin is very different from a mic for a kick drum...
Should you get a stereo mic or two matching mono mics? Do you need XLR (recommended), 1/4" (not optimal, but passable) or 1/8" (don't do it) connectors for your mic's connection to the mixer (if you get a mixer)?
You might even get away with a two-channel "field mixer XLR adapter" typically made for video camcorders... I have used Shure SM-58 mics connected via XLR cable to a BeachTek DXA-6 connected to the 1/8" stereo mic input of my G5 flat panel iMac to record some voice-over material...
So you are off to a good start by selecting an Apple laptop as your workstation... but there's a lot more to wade through.
Have fun at school!