I've had female dogs and male dogs and I think I would prefer to have a female. Male dogs are too embarressing for me when they attach themselves to your leg!

The female dogs that I have had tend to be calmer and more loyal.

I've generally found females to bark more and be a lot more high strung. I prefer male dogs, at least in the small breeds, because they tend to be more laid back and loving. Although, I've had very nice female dogs to. I don't think that gender plays a large part in their personality, especially if they are spayed/neutered.