We stayed at Exotic Caye resort. It was very nice...2-story bungalows of different sizes. I think it was on the lower end of pricing for right-on-the-beach. The pool sucks, though. It's an above ground deal that smells strongly of vinyl.
Walk to San Pedro is about 10-15 minutes depending on your clip.
Some of the others look nice too...but based on what we experienced, we felt we had the best. Ramon's gets a lot of play, but when we went to eat there, they charged us US$ for meals, at prices that we'd normally pay Belize$, and the food was mediocre.
The atmosphere was pretty touristy there...so we stayed away for the most part. Still, the dive operation just in front of Ramon's is, I think, the largest on SP.
I decided to go small for my refresher course and a night dive. Everett at Ocean Adventures (in front of Exotic Caye) is an outstanding instructor.
Wherever you stay, have fun!
Russell