I've found deer beds in many places. Hardwood ridges, deep swamps, but a favorite seems to be the tall grasses found in dried up beaver ponds. These offer excellent cover, and the deer can use their periscope like necks to peer out across the grass if need be. Moose also seem to like these areas.
I find less in these grassy areas once snow is on the ground. After a snow, deer are more likely in the hardwoods, or in dense cover to bed. On a cold morning, you may find them bedded on a sunny ridge top.