Building my first studio in my basement! Need lots of help.

Hello, I live in central New Jersey in a rather large, single-family home 1 acre from neighbors so I do not have to worry about sound bothering other people. Right now, I have a pretty large basement. Half of it is finished, and the other half is unfinished. I am a singer with recording experience, but I have ZERO experience with this kind of thing so I'd say alot of help. It's possible I'll need someone to come here to consult with me but I figured I would try this site first! Any help/tips/design ideas/layout ideas or anything anyone could give me would be greatly appreciated. The Space: It's COMPLETELY unfinished. Framework is still exposed and it's just a concrete floor. Right now I have a clear-cut 14 x24 ft space to work with, but if necessary for any reason, I could possibly go out another 5 feet on the 14ft side (but I don't know why that'd be necessary. The Budget: Well, this is open... We're looking to spend between $15,000 and $30,000 TOTAL (including equipment, etc.) The construction does not really need to be factored into the budget (the finishing of the basement, etc) because I have a family member who can do anything with ease. My needs: I am a R&B artist, so I'm pretty much going to be recording R&B vocals exclusively so I need a GREAT vocal booth... Then I want the part where all the equipment goes (Computer with protools, keyboard, etc etc.) to be in a separate room... I'm thinking that would be best to put where the door is going to be? My questions: What is the best way to lay out the room? How big should the equipment room and vocal booth be? Is there a best way to finish it? (With specific walls, specific carpet, specific stuff ON the walls?) Do I need/should i have a separate room to record instruments JUST IN CASE (this would never be a drumset or piano or anything) or should I just make it big enough so someone could sit in there with a guitar if need be? Oh... and a big thing I'm having problems thinking about is air circulation... I heard it can be bad for the equipment if its moist... The basement is Dry as a bone, so theres not much humidity in the air.. but just from people breathing and stuff. Do I need a special unit or anything that I have to factor into the construction aspect??? Basically, I need all the help I can get!!! ANY advice/layouts/plans/anything would be greatly appreciated! Thank you so much! PLEASE let me know if I need to give any other information. Thank you!!!