singular naming.
it's all about the tuples, not the tables, and a tuple is one customer, not customers. also i prefer naming in lower cases, but thats for no reason, i just learned it like that in school.
in the end, as others said, it's more a matter of preference. more important than the choice if to use plural or singular is to stay consistend and do it the same way for all tables - if you mix pluar and singular naming, it's a real mess.
