Thought I'd throw in a word about my big guy, Ranger, who is a 2 year old, almost 3, he'd like to add, Greater Swiss Mountain Dog. Most folks are more familiar with the Bernese Mountain Dog. Swissys, as they are known, are the slightly larger, short-haired version.
Swissys are WONDERFUL companions and become very attached to their family. They would never be happy separated from the pack, which means they want to be WITH you, that includes inside the house. They can be stubborn and independent, so it is important to establish from day 1 who is in charge and they always need to be on the NILIF program (nothing in life is free). For example, Ranger must sit before eating, going through doorways, etc. These guys were bred to pull carts, so they won't have any hesitation in pulling you on a leash if not trained properly and I've found that formal training classes at least for the 1st year is really helpful.
They are considered a dry mouth breed, but do slobber from time to time. It is usually when it is hot outside, in my experience. The blow their coats 2x a year, so you have to be dedicated to brushing their coats and vaccumming your house daily during this period.
Swissys are vigilant dogs. They will definitely feed off your cues as to whether or not a situation is "okay." They are really sweet dogs and friendly, unless they sense their response should be otherwise. If a Swissy barks, you KNOW something is awry, b/c they rarely bark otherwise.
I also wanted a dog who would be happy with one walk a day and not get frustrated by a lack of really heavy cardio-workouts. I have super bad knees from my former gymnastics days, so running, etc. is out for me. Swissys fit that regiment perfectly.
I can't say enough about what a wonderful companion Ranger has been to me. I will never be without a Swissy!