Whatever boot you decide to buy; take it with you and try it in the binding yourself. The binding doesn't need to be mounted, although it helps if the binding is mounted and the boots are on your feet.
An even better option; if it is possible, demo the bindings out.
Personally, I like a snug fit and prefer plastic over metal. So I'd suggest the Flux SF45 (Not sure what the new name is for this year). The Now IPO is another binding I like but it has a loose fit surf feel.