Oddly enough I'm actually ok with having one betta and his mystery snail buddy in a ten gallon right now. I could certainly add more his to his tank, but I like how it is with them now, and instead like adding more hide outs and plants.
What I really want is is twenty gallon, but preferably 35-50 gallon to replace my other ten gallon which houses my mollies, bristlenose pleco, and a couple mystery snails. Sadly that'll have to wait until we move in January. It'd be a good xmas present though (*runs to go call my parents and needle them for a tank for xmas*, I really like that I can still get decent presents from my parents even though I'm married. Yay!)