I really like the Gap Outlet in Lebanon, TN. It is really nice with some good deals.
I LOVE Opry Mills. It is all outlet stores. I have gotten Halston shoes for $60 bucks before at Off Saks. And, Charlotte Russe is nice. Some things from there suck, though.
Like the above poster, Pigeon Forge has some awesome outlet shopping. Whenever we go to our vacation house in Gatlinburg, we hit the outlets
Usually, I have found that I can always find wardrobe staples from outlets. If I want something really trendy, I know better than to look at outlets. But, if you are looking for things you can wear from year to year it is AWESOME. (By wardrobe staples, I mean jeans, shoes, t-shirts, nice blouses, jackets, skirts, little black dresses, etc.)