Re: Second pup- boy or girl?
I would go with want your personal preference is. I was always told that you shouldn't keep two dogs of the same gender together, but I know loads of people who do and they get on great. One of our neighbours has two intact males and they are fine, which I would have thought would have been a recipe for disaster. Our Gt Dane has been neutered and is very submissive, he has been great with our now 8 month old Vizsla.
I guess if you have a dominant male whether it is neutered or not it would probably be wise to go with a bitch.
This is my first time with having two dogs at one time( and if my husband has his way it will be the last :-\) so obviously not that knowledgable on this one.
You might find that youtube video posted today by Ian Dunbar about how street dogs always seem to get on together and they are mostly unaltered.