In Norway almost everybody drives 10-15 km over the speed limit.

I'm taking my drivers license now and just learning to drive (no exciting reason, just never got around to it before and didn't have a car), and I try to stay about 5 km above the limit. Fast enough to keep up with traffic, slow enough that if I'm stopped the police won't make a huge fuss. Driving AT the speed limit is downright dangerous, as everybody tries to pass you and you cause huge queues.