You often hear of the need for a strong strap, but do (reasonable quality) camera straps ever break or snap in the real world? Ok, I'm sure it has happened, but what are the chances?
With my Mamiya RB67 (my biggest camera - weighing several KGs), I just used the Mamiya strap and apart from some fraying, it held up fine. With my other cameras (including a 1Ds II with a variety of lenses), after much experimentation, I now just use Tamrac N-45s. I like the Tamracs because they are longer than most straps and have a comfortable suede shoulder bit. To me, they just feel good. I know that traditional looking camera straps aren't that popular any more, but I like them and I think that's the key to camera strap shopping. Find something that suits you, as you'll be the one wearing it.