I recently came across a new travel guide to Belize, bought it and was impressed by it.
It's Belize, A Great Destination by Kate Joynes-Burgess (Countryman Press, Woodstock, VT, 2011, 368 pp., US$19.95).
From everything I've read so far, it seems accurate, and it's very up to date. There are many photos and maps.
--Lan Sluder