What is a good DSLR camera in the 450-600 price range?

I am looking for a dslr camera in the 450-550 dollar price range. I am a filmmaker and have been without a still camera for 6 months and am getting a good tax refund back which would allow me to get a camera in that price range. I am using this as a still camera first but would like it to shoot pretty good video as well. I won't be purchasing a tripod only for on the fly shooting. In my research I've narrowed it down to two and was wondering if anyone had any experience with the Panasonic G2 or Nikon D3100 or if there is a Canon model in that price range that they can recommend. Thanks!