We love Netflix! We've had it for a year or so, and it's been great. When you drop a movie in the mail, as soon as the postal worker scans it, they send out your next one. So, it's usually no more than one or two days in between movies. You also get access to an "instant queue" as well, where there is a large pool of movies that you can watch instantly on your computer, or else stream to your tv via a video game system (I know Wii for sure, not sure if there are others) or a Roku box. We purchased a couple Roku boxes, and the picture quality is great.
We use Netflix a lot (both mail return and the instant movies), and in fact we've put our cable on hold for a few months in big part because of it. Saves us money, and with being able to see movies and tv shows through Netflix, as well as watching tv shows through hulu.com, we have no real need for cable.
Anywhoo, I highly recommend Netflix!