The X-Files (1993-2002)

I loved season seven - it was the most self-aware and self-indulgent. They clearly had more fun making it than any of the previous seasons.

That said, the early seasons - before it became all about Mulder's family and the alien conspiracy - were very good...

Oh hell, just watch 'em all in order - that's what I'm doing. I'm almost up to season 8 and the advent of Robert Patrick.