150,000 US families own a lab which is the single most popular breed.
Right now we have a 9 month old Choc Lab that just completed her OB training. Had a Rott for 11 years which is still my favorite and I might have another one within about 6 weeks...I have owned several labs, one German Shepard, and a Rott. I love all dogs so I would say just get what makes you happiest

You will just know when you find your dog
If you get a working breed training is a must...These dogs have so much natural potential and instinct that it is a shame not to develop their potential. Everyone loves labs and retrievers and they are very approachable. If you want a protector a Rott is the only way to go. The most loyal and protective breed you can get. Once the dog realizes that you are his home and family no strangers will get anywhere close without you knowing. Rotts are suspicous and always curious as to what is going on around their home. We once had some large appliances delivered and my dog was on his back legs watching in the window of the kitchen every move the men made....When they left I let him in and he followed their trail to the door and sat their for 2 hours waiting for them to return. There is nothing more intimidating that a 155lb Rott roaming around your place. Most Rotts are going to be in the 90lb-130lb range which is truly an ideal size. I thought the $2500 my dog cost was alot but I stand corrected. Dog training is one of those things that is worth every penny
I have used Mans Best Friend, they have several locations and I can always get you a great deal since I have been with Bob back when he first started.
www.mansbf.com
If anyone wants a dog from their site or info on training let me know, I promise that you will be very impressed at what they can do. They have several locations around the country and their training is $500-$2500. The $2500 is AOC(attack on command)which is inclusive of all training services they offer. I swear it was the best value I ever got for my dollar and I would have paid fourtimes as much and still felt like I got a good deal.