My favorite snow ride has been on the local mtb trail after snow fall (the Bonneville Shoreline Trail in SLC, UT). There are a few pitches that you cannot ride up because the grade is too steep (though haven't tried it w/ studded tires yet). No one is out, and once the climbing is through, there is a 3.5-mile drop (some steep, some gradual). Watching your front wheel plow through virgin powder is pure poetry -- an experience that makes your eyes moist from the joy of it all. Dead silence all around, except for the gentle 'whoosh' of the tire parting the snow and the muffled crunch of snow underneath.
A close second was about 3 weeks ago, when we had 4-6 inches dump in 2 hours. The joy in that day was the commute to work, watching all of the sorry motorists sliding around (and into each other). During all of that, I am passing this traffic jam, riding on the sidewalk [A breach in cycling etiquette, I know -- but it was complete chaos on the roads -- besides, I yielded to pedestrians]. My commute took twice as long as normal, due to the conditions, but the average motorist commute took 4x the normal. It pays to be a winter cyclist.
I've stopped using my mtb for commuting since I built up my new ride. I've attached a photo for general viewing pleasure.
Regards,
James