If you are concerned about going too big I've watched a 60 inch at roughly 12 feet for years and I think it's just about right. Doesn't provide the same in your face feel that a movie theater does, but then again that is what movie theaters are for IMO.
Keep in mind that in general picture quality improves with distance up to a certain point. If you go HUGE and sit close you'd better stick to high quality HiDef content and get a high end TV!
Home Theater: JVC RS 420, Yamaha RX-V673, NHT Super Ones/Zeroes w/Ten Sub,
Sony BDP-S5500, Darbee Darblet and Monoprice 130 inch 2.35:1 White Material Screen
Living room: Sony 60NX720, VIZIO SB4051-C0 Other: Samsung 51F8500
Displays calibrated with HCFR, i1DisplayPro, and Colormunki Photo.