^ some great advice there

Plenty of cheap and cheerful midi controllers out there, start with the cheapest you can, upgrade when (and if) you start outperforming it.

Spend as much as you can afford on monitors and a decent set of production headphones. Nothing will make as much difference to your productions as hearing whats actually happening. Especially when your are starting out, as you have to train your ears to learn how to balance mixes properly. This is very difficult to do with hifi speakers and ipod headphones.

Hold off buying any hardware until you find that you need it. There is so much great free software out there, the only thing that can't be modelled are your sound outputs.