The title pretty much explains it.
Now that we have a dedicated tag,
Is this:
the nav element and the list provide different semantical information:
The nav element communicates that we're dealing with a major navigation block
The list communicates that the links inside this navigation block form a list of items
At http://w3c.github.io/html/sections.html#the-nav-element you can see that a nav element could also contain prose.
So yes, having a list inside a nav element does add meaning.
There is a really detailed post on CSS Tricks about this exact question. It is obviously a hotly debated issue; the post has over 200 comments.
Navigation in Lists: To Be or Not To Be (CSS Tricks, Jan 2013)