I have a Contour roam for video, and I carry my Sony NEX 5N for quality shots.
I have a small case for it and it's in my tank bag in good weather and the top-box if it rains.
The trick is to keep it easily accessible. If it's not right there you'll miss the good shots. I often don't bother taking pictures if the camera is in the top box and I know I have to stop, park, get off, take off my gloves, open the top box and case...etc etc.
Young enough to know I can. Old enough to know I shouldn't. Stupid enough to do it anyway
'13 Duc Multi GT, '10 Vstrom 1k, '10 705cc KLR