There are a zillion threads on this topic (some of them a little contentious). On one thread, MirrorFinishMan contacted all the major paint manufacturers for their *official* opinions. They all said to use a glaze for the first 3-4 months so that's what I always do.
And yeah, Meg's #5 is a great one, about as user-friendly as products get. Deep Crystal Step #2 Polish is easier to find and works OK too.