I personally find it difficult to lay down 2 pair, especially if my overpair is top pair on the board. That being said, two pair can really get you in trouble. I used to play two pair way too much, thinking it was a good hand, but I found I was gettig beat by folks holding small pocket pair that flopped sets or were hitting it on the turn or losing to flush draws. Maybe I was not betting them agressive enough to get rid of people who were chasing draws.
I do find that 2 pair can pay off quite well in SnG's when the table gets down to the last 2-4 people. 2 pair can hide on a flop when you are holding one of each in your hand, instead of starting off with a pocket pair and the board flops a pair. Mid-range suited connectors seem to pay off well for me in short handed play, flopping 2 pair, flush draws and straight possibilities, sometimes the board can disguise what you are drawing after or just hit and it helps you get paid a little more.