Color doesn't really matter. Most Prof trainers will tell you they prefer Black first and foremost, then Yellow, then Choco. The only reason in the world they say that is based on what a litter was bred for.
A lot of lab mills breed for Choco or Blonde (light Yellow) because those are the colors that sell the quickest. If color is the only consideration in the breeding, and the breeding pair are selected for their propensity for producing pups of the desired color, this wouldn't be a good litter from which to pick a hunting dog. While many of them might be just fine, or fantastic for that matter, the odds of plucking a pup that will have the desired hunting qualities is higher when it comes from a hunting pedigree. Look for dogs with Hunt Test Titles or Field Trial Champions on BOTH sides or the pedigree, or from a litter where you KNOW the mother and father are BOTH top quality hunting retrievers. There are a lot of lab puppy mills out there that breed dogs with no regard for producing dogs with strong hunting qualities, good eye-sight, or sound hips and joints. They just whip out lab pups. You'll be sinking a ton of time and/or money into training a good retriever, your best bet is to start with one that has a better than average chance of making a good working retriever and living long enough to have a good career. Bottom line, if the pups are from a strong hunting pedigree then you should pick the color you like the most because it really doesn't matter.
Too many people see the retrievers on ESPN II or other places and they automatically assume that any old lab can do it. Labs are awesome dogs but the ones that will hit the water when it is 10 degrees, or sit and watch working birds with ice hanging from their snout, have a special desire and gift that only a few are born with.
Just my opinion
"I'll start spending less time with my dog and more with my wife when she starts fetching ducks for me"