I need advice, please. What camera?

[volunteerlane]

Hello all,

I am 24 years old and have been in photography all my life until about 4 years ago. I shot a Nikon N65 with Sigma lenses for most of "my career". I am now looking to get back into taking more pictures. I would consider myself an intermediate, and will be shooting a lot of wildlife and sports (and of course everything else). With technology growing so rapidly, I am out of the loop. What camera do I need to buy? I would prefer to stay below $700 to start out.

Please help me out and provide suggestions. Nikon D5000? Canon? Panasonic?

Thanks for your help!
VL