I have a question regarding the necessity of a vocal booth in a certain set up.
If the studio room is totally isolated from outside noise and inside noise is almost zero(plus the gate used while recording) and the room is acoustically treated in the best way, is it still a vocal booth necessary, besides any cosmetic purposes or the pro look that it gives?
I would say no, if your room is as quiet as you say it is and is as well treated as you say it is (hopefully on the dead side of things). Nice control rooms are a perfect spot to cut vocals. A bigger room will almost always sound better, and I think it's great to be able to simply turn your seat around and speak directly to the talent. Plus, you can cut vocals with the monitors on if you have Bono coming over!
I mostly agree with David, but on the flip-side to that, it IS nice to have another isolated chamber in your studio if you want to throw a cabinet or something in there for seperation. In fact, 9 times out of 10 there's an amp set up in my vocal booth and I'll record the vox in the control room. Is it a necessity? Probably not, but definately a nice thing to have if you have the room and $$.
I like mostly record in the control booth myself as I do a lot of solo work but vocal booths are good to have, especially for voice-overs.