I'm still going to go with a raptor or two, and probably get a case w/o a window and seal it up with accoustic foam. Possibly get some sort of internal fans if the sound damping works well.
You only get so much extra PERFORMANCE out of those 8 extra case fans needed for that overclock. For me there are just too many times when I don't want small windstorm brewing next to me. I'm going to be living/working in pretty close proximity to this thing in my dorm room.
Random rig info: I also plan on buying the gigabyte 6600GT with the completely passive cooling design. It's nice