I'm currently on my third year of Prime. I got it before they added free streaming or lending library. With the edition of the lending library, I decided that my next ereader will be a Kindle.
I'm the type of person who would rather order something online then deal with people so I really get my moneys worth. Then again, it has only cost me a total of $40 for my three years of membership...
On average I get about half of my Prime 2-day shipped items next day. I have even received same day delivery on a couple of items I paid the $3.99 next day shipping on. (I'm pretty close to a distribution center).
Now that Amazon streaming is available on PS3 and Xbox360, I have recently started using it. I cancelled my Netflix subscription when they lost the Stars contract. I have found tons of great things (most of which are free) to watch on here. They have been steadily adding some great content.
I will certainly renew my subscription for a fourth year when the time comes. I'll even be willing to pay full price for a change.