Market St. is (duh!) where the huge market is. I imagine some of it is open over the holidays. King St. is the shopping St. There's a high end bag and shoe store called Bob Ellis. And a local purse maker, Moo Roo, has changed to Mary Norton (woman who started Moo Roo)--I read they are in a new store on King St. Lots of nice shopping. also take a peek into the lobby of the Charleston Place hotel--old fashioned and they have a little gallery of shops.
Other fun things are a walk down Rainbow Row with the pastel houses and a ghost tour walk at night. (not sure if they run in winter, tho) Lots of great restaurants (82 Queen is coasting on past reputation; skip it even tho it's usually written up in the guide books)
Have fun!!!