Ahh yes. That's my Dog. Greatest dog breed ever, English Mastiff. (excuse my "Giant dog" snobbery.. I started studying them years ago before I ever bought one, and continued to do so ever since... and I married an animal expert who works in the field, so I have to keep up on it to be able to converse with her)
Most of those pics posted are fake or sort of taken at an angle to look bigger, sort of like the fisherman holding the fish strait out while posing for a picture so it looks larger on camera.
The first one is in the Mastiff family, It looks like a Boerboel or South African Mastiff. Not 100% sure. It's to big to be a Bull Mastiff.
The second pic with the horse in it is a known fake but its of a Neapolitan Mastiff, the same kind that Hagrid has in Harry Potter.
The third one is of an English Mastiff (the same one I have). I am pretty sure that picture is real though. Though that is not Zorba, only one picture of him exists and its sort of sucky.
I have a 20 month old and my dog Angus is the greatest with him.. though you always have to be careful when he rolls over on his back, he could injure by squishing him on accident. I have 4 dogs and will always have a mastiff, when Angus goes, we'll get another. Right now he is like 220 something, he lost weight after his recent knee surgery. Was around 245lb at the most. He's around 5 and a half now, which is getting in the "mature" stage for a larger male. So to keep him around the longest we can we are trying to get him down to 211. We've been feeding him less, but he just ends up eating all the other dogs food. He's a challenge sometimes.
If you want one Dogg, (and don't want a puppy) there is a great rescue ClickIt's the Great Lakes Mastiff Rescue, I think it covers Chi-town as well.
I personally like having a giant breed from a puppy, because they need to be raised firmly and you need to be very dominant over them, (not that they are a stubborn or dominant dog, but because they are so huge and powerful you need to have 100% control over them.. if a small dog or even a lab snaps at you for some reason, its easy to forgive; if a 200lb dog snaps at you, its quite intimidating).
But I think we always will own one. It's amazing how safe you feel in your home. We live alone in the woods, some distance from neighbors and we feel as safe as can be. The dog isn't aggressive towards strangers, but the nature of the dog is to put himself between you and the stranger. The dog will always be nice, but he'll put a boundary down and enforce it. It's sort of neat watching it. I had a friend come over and kept telling him to walk this way then the other.. and Angus stayed within 2 feet of me, but cut off the angle between him and myself the whole way.
Since we had our child, he does seem to act slightly more aggressive towards strangers when our son is around. By aggressive I mean he will leave our side and cut the distance in half between us and the stranger and say "No.. not gonna happen". The most intimidating thing about him is the fact you can actually feel his growl before you can hear it. I have no idea how that is possible.
I don't have any good current pictures of him on my work computer (where i'm at now), or I would post some.