Traditionally I do the good majority of my Christmas shopping online. To me it just makes sense. 1) I have almost no time to go walking around a mall for hours on end looking for the perfect gift, 2) while I really enjoy the company of a good friend and meeting new people - the mall around the holidays is not my cup of tea (I hate pushing, shoving, and rude people), and 3) I can shop multiple stores for the same product, find the best price, and get it shipped to my door in a matter of minutes.
I've bought some of the best gifts ever from e-bay, and they're not always "new". I have often bought refurbished products, or delicately used items, and used them as gifts. (with 7 kids you learn to be frugal really fast if you want to enjoy other things in life, like new cars or vacations)
While e-bay is probably one of my favorite sites of all time, I also shop big box stores (Kmart, Walmart, Sears, etc.) online as well. I have ran across some of the best deals ever on sites I hadn't heard of before the day I found my deal.
Do you shop online? What do you shop for online? What's your favorite store/site to shop online?