Hi Aegir:
I took my snorkel off of my mask several years ago. On those occasions where I surface swim in scuba I usually prefer to do it on my back anyway, and I just don't like to snorkel in scuba gear. Initially I just put my old snorkel in my BC pocket. That didn't work out so great because it was one of those snorkels with a rigid breathing tube connected to a flexible corrugated tube leading to the mouthpiece. The corrugated tube would sometimes fall off the rigid part when folded in my pocket.
I now have one of Scubapro's two piece hinged folding snorkels that I keep in my BC pocket. It hasn't fallen apart (yet), it doesn't get in the way, it meets certain dive op's requirements for having a snorkel with you, and Scubapro's quick connect latch for the mask will come in handy if I have to get in the water right quick to freedive with that whaleshark. But that's all the "nice" that I can say about it. It's a pretty crummy snorkel IMHO (breathes wet, a 2-piece snorkel really isn't the best idea, etc.) and it was way too expensive. It does suit the purpose that I intend it for, but to be honest I think I would probably be better served by a one-piece rigid tube snorkel that I let partly dangle out of my too small BC pocket than what I have now. Simpler is better. I haven't tried any of the smooth but flexible one piece tube snorkels.
HTH,
Bill