Specialized sells really awesome tires. They are a bit expensive but well worth the price. I use the crossroads that have the flak jacket built in. Here's their site: http://Specialized.com
I had a pair of Crossroads armadillos, I put 7-8000 miles on them
didn't like the red sidewall band much tho
I have heard good reviews on the Serfas city drifters, they can be found for around $30
I am hoping for a pair for my b-day in May, if I don't get a set sooner LOL