Not water dogs, but some of very best dogs we've ever had were Australian Cattle Dogs (often referred to as Heelers). Medium sized, rugged, affectionate, easy care, and extremely intelligent. This working breed hasn't been ruined by AKC conformation dogshow breed bullshit.
Tilly (our ACD) actually surprised me and was very much a water dog.
She was the awesomest - if we find the acreage we want, we're getting another!!
cheers