Update: I have now settled down with all lowercase tag names.
Camel case is too 'heavy' for tag names; especially if many are put together.
Following is my old view that has since changed:
I suggest that tag names should remain case-insensitive but should be displayed with proper casing i.e. camel case.
At minimum: I suggest- there be a user specific option to choose how it's displayed per user according to his preference.