dabbyl

Ignore that last message...

Um, if you want a keyboard, make sure it is USB Midi compatible. Makes it easier to use with your DAW.

Computer?

It doesn't matter. I would preferrably get a desktop, but laptops work fine if you have enough USB ports, etc.

I don't think there would be much difference with what OS you use. I would just make sure you have a good sound card and high-speed processor.

A Synthesizer?

Can't really help you.

If it is a software synth, then, well... yeah.

But if it is hardware, then you should probably get a program to record it, like Audacity, then take that WAV and import it into Fruity loops.