My top choices would be Colton House, across from the Radisson in a safe area and close to good restaurants -- beautiful 1920 West Indies-style house with five B&B-style rooms (though you don't get breakfast). Alan and Ondina Colton are great people, and they have an excellent library of Belize books and tapes. Around US$60-$70 double. Also, Villa Boscardi, in the upscale Buttonwood Bay area between the international airport and downtown. Beautiful B&B. Breakfast included and they have a free shuttle to and from the airport. US$65 double.
Grand Residence also looks nice although I haven't stayed there myself.
--Lan Sluder www.belizefirst.com