I like my Schwalbe Marathon Plus 32's. They are heavy but bullet proof so far. I think they are better than the Gatorskins or Armadillos because in addition to the tough lining, they have a much thicker tread and sidewall.

Here's a thread about them.

I think that 28 or 32 tires are the best compromise between speed and comfort for commuting. Narrower than that, you have a tough ride and it's too easy to get your tires stuck in pavement cracks. Wider than that and you have to use such low psi's that it really slows you down. But it's a trade off, and there's really no one right answer.

[Edit: I added the third sentence to the first paragraph.]