Residential - 14 Lighting, 12 receptacles. Especially in can light runs and 3 or 4 way switched legs like Speedy Petey said.
Every once in a while 14 has been used for a 15a receptacle run, but not often.
Commercial - 12 is min. in our town.
[sea story]BTW - anybody ever hear of the EC in Chicago many years ago (60's), who was installing 12 for the first and last 2-3 feet of the run, and using 14 inbetween? He was doing a lot of big apartment buildings, and apparantly (back in the day) the cost dofference was significant.
Chicago AHJ found out, and not only hit himn for the 'discovery' site, they pulled all his tickets for the previous 4-5 years, and went back and reinspected. Turns out he'd been doing it for quite a while. Penalized him for all they could under statute of limitations.
Guess the 'cost savings' wasn;t so great after all...[/sea story]