A Lab can definately make a great family pet - good examples of the breed are laid back, friendly and very tolerant. Of course in order to ensure this in any breed, puppy classes and socialisation are a must. The only thing I would say about Labs (having one myself) is that they shed A LOT!
I'm always opening sealed crisp packets and finding Wilbur hair inside! Male Labs can be slightly pungent, even when neutered, but they're worth it - it isn't too bad unless they've rolled in something.
Where to get one from depends on what you want. If you'd prefer an older dog (they will be more sensible and calm, probably housebroken etc) then I'd try a Labrador rescue oranisation. If you really want a pup, you'll need to check out your breeder thoroughly - are the parents hip/eye scored, can you see at least the mum, where are they kept etc. If the breeder seems more concerned with getting your money than asking about the dog's new home, be suspicious!
Then with either breed there's the queston of whether you want show strain or working strain. With Labs, show strain tend to be much larger and stronger, but also very laid back. Working types tend to be smaller and lighter but need a lot of mental stimulation as they were bred to work, and may be more lively. Of course every dog is individual, but that's a general trend.
I've never owned a Golden (my other dog is half Golden, but isn't a lot like one) so I can only recommend a Lab, really. Anyway good luck with your choice, well done for doing your research and I hope this helped!