Wow. You name two incredibly overrated movies, and one movie which deserves it's status entirely.
Don't like Citizen Kane...? I mean, you're free to your own opinion, it's just hard to come to terms with the fact that such a perspective is physically possible.
Back to Saw: WTF? It's terrible and the only good thing in it is Henry Gale. It's a joke of a movie. Se7en is the only one of that genre I've ever thought anything of, though... mostly they just come across as pointless sadism for incredibly tenuous reasons.