...sigh... tires, a world of preference, black magic, and rubber. When I did ride fixed, it was on Rubinos, and they did wear rather quickly, but I didn't use any other tires for long enough to make any relevant comparisons. The only other models I used were Michelin Speediums and Zaffiros.

I don't know about using a GP4K for riding fixed, because that's a race tire, so it will use softer/tackier rubber, which ought to wear faster... Maybe Specialized Armadillos work well for street fixed riding?