My specs:
Macbook Pro 15" running 10.6.8; 2.4 GHz Intel Core i5; Ram of 4 gb & 150gb left on hardrive

I'm looking to create house music and other similar genres. I'm on a low budget since I'm starting college next year.
So for my graduation gift, I assembled this list of things:

While I'm interested in recommendations for what I've already listed, mainly I'm concerned about what I'm missing from my list.

Do I need an audio interface, or can I use the midi-usb adapter and it's good enough?