As with Jomebrew, I primary all my ales with no secondary. I primary for 3-4 weeks rather than 2:
1. Because I'm too lazy to check the SG repeatedly to be sure its finished....and, I'm not in any rush.
2. I like a little clearer beer than I can get in the 2 week time-frame. But, then I can't cold-crash...so, I need the extra time. Even still the beer clears out further in the keg significantly.
Fermentation is mostly driven by yeast strain. Assuming your using a standard ale yeast of either American or English variety the above should work just fine.
The more important question that you did NOT ask, is what temperature should you use....that will have much more impact on the resulting beer flavor than whether you transfer to a carboy half-way through.
I've gone to cooler temperatures for most everything, because I'm on a cleaner flavor kick these days. Cooler=64-66F for me versus 68-70 of years past. I'm actually pitching at 60F, and then letting it free-rise up to ~64. After 3 days, I raise the temp to ~66-67, and hold it there for the remainder.
-tch
Same for me.