I personally don't like store-bought extended warranties, and depending on the hassle they put you through to redeem it, it may or may not be worth it to you, but that's a personal choice.
I will say this about the D7000's video quality. It's much-improved over the D90's. I just did some video tests with my D90 moments ago, and on a 52" screen, you'll see huge chroma and luminance aliasing (gradients appear as discrete "bands") whereas the D7000's video has no such artifacting. None. This is a huge improvement in image capture/processing quality. In comparison to the D90, the video quality from the D7000 is of very high caliber, probably approaching that of very expensive digital cinema cameras, many times the cost of a D7000.
I forgot to mention one more thing--no "stair-stepping" in the D7000's video, as is prevalent in the D90's video. At least in the handful of clips that I shot with my D7000, I see no evidence of that awful stair-stepping present in the D90-acquired video.
Again, in low- to moderate-ISO video photography, you'll likely NEVER see any single-pixel issues on the D7000. If you crank the gain up on any camera, you're likely to reveal a few dead pixels. The video I shot at ISO250, and even at ISO1600, looks perfect. Only at ISO3200, framing something black, where the blue pixel is, do I even see it. However, this was a specific concern for me since, I plan on doing a lot of car-mount, night-scene video photography, where I will have a lot of shadow area in my frame, exactly in the spot where the pixel at issue is located.