LostSoul
Adventurer
It seems 4e has a big swing for combat length. Like for my own campaigns combat so far has always been around the 20 minute range. I think part of it is I really like to ramp up a feel of tension and speed, a very much a "go, go, go!" deal so Power choices are decided faster, etc.
It's player-dependant. The guys in my game like to take some time to consider things... which I discourage, but I can see why it happens. So much to consider! It's like chess, very complex (in a good way).