We only have males in the house at the moment(three of them. ), and I'd have to say that I'd go with males.. though I've never, in my life, owned a female dog.
I've been around female dogs plenty... but as many do, I find the males to be more laid back. I love dogs that aren't too hyperactive, but a little hyperactiveness never hurt.
Both genders have their good points and all, but I definately would own a male dog over a female dog.