Personally, I am a fan of the Saw series. My favorite trap was the lover's triangle. I felt kind of sorry for the girl.
I forget which sequel in the series I left off with. I think the 5th. Never saw the 3D one - was that the last one? I don't recall seeing one released this past Halloween.
I suppose I enjoyed them okay at the time but I don't remember much about any particular entry - aside from Cary Elwes wretched acting in the first one. That and Leigh Whannell's sexy bare feet.