Definitely worth renting once it comes out to video. I saw it twice, and I'm a fan. It definitely has a good plot, which makes up for the large amount of philisophical issues posed in the matrix that identity did not have.
I was pleased to be wrong a few times when I had thought I figured it out.
Anyone who enjoys a good plot and a good thrill (I was definitely on the edge of my seat quite a lot) should invest the time and money to see this flick.