Just bought a D5100 and can't imagine having more features to learn. Also, I checked the release dates and the 5000 was April 2009, 5100 was April 2011. I'd bet the 5200 is another year out, and if they change the display again, I'd rather have the 5100. I've been shooting Canons since I went digital and got hooked on the fully articulating screen right off. Candids are Sooo easy, since half the time people think I'm chipping when I'm still shooting!
Anyway, thanks to Russ McDonald for steering me toward Nikon. My first 1,000 frames are nearly all winners, and I've only had the camera since Sunday!
Summary - don't put off a Nikon you can purchase today. Just do it!