Getting my first camera.

So, I'm in the market for my first "nice" camera. I'm going into a biology major so most of the pictures I would take would be of landscapes or wildlife because I love the outdoors. I know a decent amount about photography and two of my close friends are very good photographers. So I'm not looking for something that is to simple. I would like a camera that is geared to be slightly more aggressive and complicated so I can grow with it. Something with interchangeable lenses would be great, but i'm not limiting myself to a dslr. My price range is around 600 on the high end, but I'm willing to goop higher if it is going to be worth it. Thanks for the help!