Short sides & back, a bit longer on the top, sideburns cut off straight seems to be a pretty common male haircut. A buzzcut that is the same length all over can emphasize a feminine skull, as others have said. Keeping the hair a bit longer on top (maybe 1" if the back/sides are 1/4") seems to prevent that from happening. It requires minimal work, except for the fact that you'll need a haircut at least monthly to keep it short. Or you could just be me, stop caring, and leave it go for 6 months.