I guess for me, it's going to hurt just as bad at 8 years as it will at 12 or 16 so I am not going to base anything on how long they may live. I am going to go with breeds (or mixes) I have a strong connection with and enjoy them for as long as I am blessed with them in my life.
The thing that gets me about giant breeds living less than 10 years is they are so slow maturing. It takes a deerhound about 4 years to mature. Then what, you have them maybe 3 or 4 more as an adult? Sad. When I invest the time and energy in loving and training a puppy, I'd prefer if they stuck around for a while longer than that.
Borzois are awesome because 12-14 years is pretty typical, which is a long time for a giant breed. I've met a couple who hit 15, and they weren't particularly geriatric acting or anything.