To me, S1 and S2 are neck and neck, with S3 and S4 so far behind they aren't even visible. That's not to say that the latter two seasons don't have some terrific shows (as I mentioned in another thread, if I had to choose a single favourite episode, it would be S3's Ordinary People), as well as having some terrific moments in otherwise poor shows, but as a whole, the latter two seasons were too unbelievable (even for LnC), too soap-ish, and too into the occult for my tastes. S1 and S2 were much lighter, more full of optimism, and generally more interesting.

Just MHO.

Joy,
Lynn