This is all just my personal opinion... For a family pet you probably want to go for American Showlines or a mix of American and German Showlines. I'd pick the latter for looks because they don't tend to have (the crippled Am lines look - over-exaggerated slopping back) or (the "banana" back of the German showline dogs) the mix seems to cross eachother out - back wise. They both have a totally different look, and that is just the showline GSDs. Now, the showline GSDs are totally different in temperment(actually everything) than the working dogs. The working dogs have all the brains and physical ability.
The German workline line GSDs can be hardcore, and being working dogs, need a job. If you have a job for your dog, get a workling line GSD. I love the look of the working line GSDs best but looks aren't everything, you want a dog you can live with. If you are interested in schutzhund go with a DDR GSD or want a police dog go for a Czech GSD. Just to get an idea of where each type is at.
Research what you want, there is a huge differnce between an Am Showline GSD and German Working line GSDs to the point that I think they should be considered seperate breeds. The different types of the breed gets difficult, my best advice is go to a lot of different breeders, find out all about the different types and meet the dogs.