MBA 13" for Uni and Music

A Macbook Air with those specs should be able to handle that comfortably. Of course, that depends on how many cpu hungry plugins you will use at the same time. But if your compositions are a little like mine, it will look like a drum plug in a la EZ drummer, bass with some amp sim, about 3-4 guitars with amp sims (i use amplitube or Logic amp sim), maybe some software-generated keys, and some vocal-tracks with plugins. The MBA you mention should be able to handle this very nicely. My iMac (from 2007...) and my 2011 MBP can handle this with ease.
br. andershoeg

 

You're welcome.
The use of a Line 6 could be one way to cut down cpu usage (not that I think that you need that). But, depending on your DAW, you could also just freeze some tracks when needed. That way, you still have the opportunity to edit the the guitars, amps, etc. after they are recorded (you can edit the eq a bit, but not be able to e.g. take out some gain).
I can't really see a reason to go with the pro instead. They have got more cpu power.....but do you need it? The airs also got this super fast ssd drive, which will serve you well when handling a lot of audio tracks, trick samples etc. (when samples is loaded they use the RAM, therefor good idea to max out on this one. Can't be upgraded later on the Airs!).
I've got a 13" Pro, and actually I am thinking of getting a 11" air (again....). Got the 2010 version, and it was a little rough on my eyes. But the zoom functions that has come with Lion and Mountain Lion is fantastic. So I'm considering....
Feel free to ask any more questions! (And pardon my english, the grammar probably isn't correct.....I'm danish ).
b.r. andershoeg

 

About what limits you would reach it's hard to say. I can't imagine other "bottlenecks" than the cpu sometime in the future being too slow. But then you will be doing a lot of soft synths, etc.! And by that time it is probably the time to buy a new mac ;-) As I see it, you won't run into problems. The Air has got the thunderbolt connection, with adapters for firewire interfaces etc. Not to forget USB 3. So I think you are future proof regarding that.
About recording a kit with multiple mic's, that will not be a problem! I have recorded kits with 10 mic's on an old iBook G4. The recording will not be a problem. Of course, there IS a limit of how many plugins you can use at the same time. But I don't think you will have any problems, as long as your projects isn't any bigger than what you describe. Just tested an old recording I had on my Macbook Pro, with ten drum mic's, one bass w. amp-sim, five guitars, and about 3-4 plugins on each individual track, plus 3 subgroups and the master "channel", all with about 4-5 pluins on each. The cpu meter tells me I'm using about 20-25 % cpu, and about 20 % read capacity from the HD. All this without freezing any tracks. But ok, there is no vst's or such things running. They tend to use cpu. But all in all, I think you are more than good to go, with the machine you mention! If it was me, I wouldn't worry!
B.r. andershoeg

 

You're welcome. No, I'm not experiencing any latency issues. I'm using either a M-audio Firewire Solo interface, or a Apogee Jam. The Jam is really nice, I think!
Good luck with your setup. It is going to be a nice one!
B.r. andershoeg