What tire clearance have you got? Plenty of folks (including myself) will tell you to buy Compass tires and don't look back. I never knew what great tires felt like until I rode their 32c tires.

Another option are the Rivendell Ruffy Tuffy 28c tires. While bulletproof, they aren't as comfortable I find as Compass tires. They'll likely last for years, though, so ultimately it depends what you're after.

I'm waiting on Compass 35c tires to arrive at my LBS, and even though they cost quite a bit here in Canada I believe them to be worth it.