What I like most about cold weather is that I can usually run faster with much less effort because my body is not working as hard to keep cool, as long as I wear appropriate gear to keep it from having to work hard to stay warm :) I also don't have to get up as early just to get in a run before it gets too hot. At the right time of year, I could go run at noon! Although not related to running, I also love wearing sweaters and scarfs :)
What I like least is having to bundle up to run when it's really cold. I don't feel very motivated to go for a short run in the cold when I have to spend longer getting ready than the running itself. It's hard to determine before starting just how much to wear to strike the right balance of staying warm and not overheating. I usually have it all figured out by the end of the season, but promptly forget and have to relearn it all the next year.
Thankfully, I live in Florida so we don't have to deal with snow or sub-freezing temps. How about you? What do you like most and least about cold weather when running or in general?