Any upgrade their tires?

[Savage]

Other than blimpman, has anyone else put on some meatier tires yet? I forsee myself doing more fun dirt riding on this thang than I do general commuting. So I'm wanting to get some beefier tires and just shopping for some inexpensive options.
I suppose a big knobby tire would look "cooler" siting at traffic lights too. lol But that's not why I want them.

Any pics or links? TY