I can recommend Continental Gatorskins. If you're running 700x23 right now, the Conti 700x25c are the same width. They are a pretty fast rolling tire, although a bit heavy. I've run over glass, sharp rocks, and metal shards with no problems yet. From the reviews online, I think that is the norm. I've got almost 1,000 miles on them so far and no flats. Many people are running these tires for 2,000 miles before they need a replacement. That's a good thing, because they are a bit spendy at $45 a pop.

http://www.rei.com/product/671870?pr...:referralID=NA