+1 for maxxis. Got a set of diamonds on the gen II atm, and I ride hard all the time (got another bike for cruising on which has supermaxx on it).
The rear has worn out now, but it's lasted just as long as the PR3, and the contimotion's I had before it. I get about 2500 out of a rear, that's giving them far more abuse than they deserve!
The diamonds are very good once you get used to the strange profile, I've edged the rear with ease and confidence. A few foc-ers saw my rear tyre on the last meet, and the wear is pretty even. They're excellent grip from cold, and good in the wet, although I don't ride hard in the wet, it ain't worth it!
To top it all, it's about £100 fitted for a rear!