I use Black Magic Tire Wet Express. It lasts through at least 2 washes unless I scrub the tires.
Here is a link to check out the 303 products. I use the aerospace protectant for just about everything in my car and also use it to keep my chrome wheels more resistant to brake dust.
Check out the testimonials and other uses. It's a very cool product line.
303 Products Inc.: Technical Guide to 303 Products