Very large breed dogs?

I love large breed dogs (like those in the 90-200 lb range), but I don't love some of the traits that generally accompany the size. Hip and joint problems, short life span, etc. I understand that each dog is an individual, breeding counts, etc, but 7 years just seems like a very short life! I want my cuddly, massive giant, but I'm not sure I can handle only having him a few years. So, can you help me out? What are some of the healthiest, longest-lived large breeds?