I completely disagree that labs have been "wrecked" as a pp put it. That is WILDLY offensive and a ridiculous sweeping statement.
The last time there was a dual champion was 1946- i.e. a dog that had been made a champion in both the ring and the field. However there are many Champions around today- dogs who have become show champions and then have had to take their show gundog working certificate to show they can do their original gun dog work.
There are several kennels who try and ensure that their show bred labradors retain their working abilities- off the top of my head Warringah is the highest in volume one i think, Carpenny, Naiken, Millerdan, Affinmore, Fabraken, plus lots of other small time hobby breeders.
However, as much as no one is denying that the show type lab has become stockier over the years, this discussion seems to be missing that the working type have also gone the other way and become much leaner and finer- and actually many could not do their ORIGINAL job anymore- i.e. they are now built for speed and agility required in field trials, but do not have the all day staying power, and strength and stamina that previous generations did- BOTH sides have deviated from their original purpose! Both sides of the breed were breeding for different things in mind at the expense of the other.
Some examples of full champions: Warringah
A field trial champion from a very famous working type kennel drakeshead.com/gallery_images.asp?gallery=Indiana
The last ever dual champion www.thelabradorretrieverclub.com/articles/imgC5.gif he is far more moderate than either extreme now!
An article explaining it better than i ever could dual purpose labs
In an attempt to be entirely transparent- I do have show type labradors. I have previously shown them, and hope to show our puppy next year, I would love to qualify for crufts- in such a high numerical breed like labs, that would be a huge deal to a small time novice like myself. My older bitch isn't shown, but does agility with my son, after dabbling a little in basic gundog training. She is purely show bred and weighs in at around 31kg ish.