I'm split on this one. Some sequels are well worth it, they're well done and fun to watch. Other times you can tell that the sequel was just made to grab dollars, and those aren't so great. The Ring, for example, was a very good movie that I quite thoroughly enjoyed. The Ring Two, though, sucked. What I dislike most about sequels, I think, is the amount of time you have to wait for them to come out. Two, sometimes three years between movies can seem like an eternity, if the movies are good. (Like the Harry Potter ones)

Some are good, some are bad. Some are continuations of the original story (such as for the Matrix, Star Wars and Lord of the Rings trilogies), and are pretty good. Some are just outward attempts to draw more money from the success of the original (Hey, people liked The Mummy, let's make a crappy sequel, people will watch it).