I made the difficult but right choice not to run today. Still have this cold, which seemed to have peaked last night. Still feeling crappy, but can tell I'm getting better.
I'm a bit concerned of missing my long run today as a result. Next week begins the taper period. I'll still do a long run a week from today, and may follow Mark's suggestion of running 10 miles next Sunday at a somewhat relaxed pace, and time the end of that segment to coincide with the start of the Mid-Winter 10-mile Classic race and run that at MP.