I ride Schwalbe Marathon Supremes on my 520. I like em'. Good puncture resistance, roll fast enough. I feel like they're unnecessarily expensive though. I bought some awesome puncture resistant Michelins' (sp.) for my Surly and they were half the price per tire that the Schwalbes were! Same quality. It's kind of a gamble, really.

If you can easily afford the Schwalbes, do it.

If you can't, keep searching and you'll find some that will do the trick.