I think it's sad that so many people seem 'duty bound' to spend time with people they really don't particularly want to see.
Like a PP, we never got into the pattern of doing the same sort of thing year after year ... we mix it up, see people, don't see people, volunteer, stay home alone, go abroad ... no one in our wider family is offended, last year my DH & I spent Christmas separately, people thought we were 'odd' but it worked for us.
I am at the age where I may soon be a MIL, I would hate to think of my adult DS feeling 'obliged' to spend Christmas with me and I hope I will be sensitive enough to be able to make my own plans. My own elderly parents often say they are more than happy to spend time alone at home, travelling around the country is usually awful at this time of year, as is squashing into some one else house and trying to fit into their routine not to mention over excited grandchildren.