With awesome strength, impressive smarts, and a gentle spirit, Saint Bernards are the ultimate family guard dog. They are loyal and loving and unfaltering in their protective nature toward their families, especially kids. Assuming you can put up with a bit of drool, the Saint Bernard may be the perfect pet for you.
Traditionally, Saint Bernards worked in the Swiss Alps rescuing avalanche-trapped travelers. This is good to keep in mind -- you never know when you or someone you love might need to be pulled from a snow bank. The only potential downside to adopting this breed (other than the drool) is that it needs space to roam. Saint Bernards generally don't do well when confined to small spaces.
If you're planning to adopt a Saint Bernard, remember to train early and often. They key to good behavior for Saint Bernards and all dogs is to socialize them throughout their lives. Remember that you cannot train the guarding instinct out of a dog, but you can (and should) fine tune it so that it's used appropriately.