I really don't like anything on my deck except my water bottle, and
occasionally a chart and a compass. That said, these days I paddle a very low
volume kayak in which I can fit pretty much nothing inside the cockpit besides
myself. So I have a deck bag in which I carry my water bottle, pump, throw/tow
rope, a webbing loop for loop rescues, a baggie for on the water bladder
relief, a paddling jacket (if I'm not wearing it) and snacks and such. I no
longer carry a paddlefloat as I find it overly redundant for my own particular
case.
I suppose technically having a deck bag can raise the center of gravity of
the boat some, but I sure haven't felt it. And while the bag is waterproof, I
never think of it as such and don't put anything in it that I am concerned
about getting wet unless it is in a separate waterproof bag within the deckbag.

Scott
So.Cal.