oh man...go with a DOBERMAN. we (home away from college) have a doberman mix, and winston (boxer), and next door lives the most beautiful black and rust doberman. so elegant. he's about 3 years old and wonderfully trained. the three love to play together. what a combination...an AKC boxer and a doberman. i think all the positive traits possible in dogs would just about be covered.
a doberman really is my dream dog. they can be quite expensive if not adopted, but once i am stable (out of college), that is my next animal-investment.
our dobe mix, asia, is virtually 100% doberman with GSD fur; personality, bodytype and everything. as with any dog, it is important that you hand pick the dog to your liking (personality traits). believe me that between the boxer and doberman, your family is safe, five times over.
i personally would never get a blah-lab...too "run of the mill". lean muscular (fairly intimidating looking) dogs are the type for me.
good luck, and check out some books on the breed that seems to fit your preference.
jim