It's a tough one. I've got a scraggly terrier that I'd love to take fishing with me. I've only taken her with me a couple of times and it was hassle so I'm inclined to agree with CM's comments.
I love the image of the lab fetching every cast!!!
I'd say it very much depends on where you are fishing and how much control you have over your dog.
I know I can't trust mine to stay in the swim and it will jump up at every walker by, oh and definately take my rods out a couple of times!
If your lake is quiet and you know the other anglers are fine with all potential dog behaviour, then go for it, but I thnk if your worried it may be best to leave dog at home.