imho, just a latop/pc with audio interface, you be good to go.
As for what audio interface, offering from lexicon, m audio do have some good deal and come bundled with software to do recording, editing, sequencing and midi programming. Usually the basic unit will still cost couple hundred, but less than 800 for sure..Those bundled software usually is the simpler version, but you still can do lotsa thing with it. And if it support various (freeware/shareware)vsti, vst plug-in you can further expand on the usage
anyway, do check out the computer and sound forum in soft, theres some really good info which might be useful to you.