There's a thread about cheap tires. A few mentioned Kenda Kwest as their choice.

I used them and in fact just picked up a pair of 700x28c for my roadie for commuting duties. The price is fantastic. It also came with reflective strips. In the past, I used Kwest 26x1.5 and they were fine. Went through all sorts of stuff. Can't find a good reason to switch to something else yet. Hopefully the 28c will yield just as good an experience as the other one.

I guess in its price class, you may consider the Conti Ultra Sport or Michelin City-something. Specialized Nimbus (non armadillo) is also another alternative.