Home Studio Soundproofing

so im a producer and artist, and make beats on flstudio 9 mpc 1,000 and korg triton extreme 88key keybord on a imac ran with boot camp and windows xp. so im wanting to set up a home studio with a booth in my walk in closet(padded and all), protools and my imac(ran on the mac side of the computer). what stuff do you guys recommended me to get thats worth the price like mic pre amp the hole nine yards etc etc to set up a knockin home studio? also just a side note all the post production like mixing and mastering will be handled by my friend who went to full sail and did a internship with the clipse straight out of school for a little over a year so the post production will be professional industry ready from what ever stuff i record at the house with, and may even be ran through the ssl mixing bord were he works at now. reason i am telling you this is so you don’t tell me any thing that i need that has to do with mixing and mastering, and so what you guys recommend me can work great/make it easier for him with the post production.

It sounds like you already have a pretty good setup. All that is missing is a USB audio interface:

http://www.zzounds.com/item–TASUS1641