I'm less okay with the silver aspect. It just gives them too many weaknesses. Back when these legends were still very much believed in, only the aristocracy and very well-to-do individuals were likely to own silver. Everybody else was screwed. Today, pretty much everyone has a sterling something-or-other in their home. It's even used to line mirrors (which may be a secondary reason for vampires not appearing in them, though the most often cited reason is the lack of a soul). I always thought garlic was a bit silly, too.