Here is a list of some (there are so many more beyond this list!) direct sales companies that are fairly well-known and seem to be among the more popular ones:
Pampered Chef (kitchen supplies)
Usborne Books (children's books)
Tastefully Simple (food)
Scentsy (scent warmers) **Very Popular--make sure your area is not too saturated with reps already**
Celebrating Home (home items)
Thirty One Gifts (personalized products, bags) ** I read they have a hiring freeze starting 2-8-11** One of the fastest growing companies in direct sales right now!
It Works (weight loss)
Silpada (jewelry)
Lia Sophia (jewelry)
Avon (make up and more)
Dove Chocolate (chocolate)
Arbonne (make-up)
Mary Kay (make-up)
Slumber Parties (adult)
Passion Parties (adult) **Also very hot right now**
Creative Memories (scrapbooking)