I bought the D5100 primarily to play around with video. It has OK video performance and an articulated LCD, which makes it great for the purpose. I have shot some video, but not really gotten started yet, but I have on the other hand shot tonnes of stills with this camera, which is much like my beloved D40, but just with a much better resolution and image quality. In terms of size, weight and handling, it's a very worthy heir to my D40, which I always love using in spite of its inferior performance compared to the D200 and D300s.
I wanted to fool around with DSLR-video and this was a very inexpensive way to get started.