Looking for recommendation for camcorder

[pengyou]

I want to buy a camcorder now that has enough features to help me learn how to ultimately use a "real" one proficiently. By real I mean HD+ The camera that I want to ultimately buy is (right now) about $900 at a discount price.

I need to be able to learn how to shoot video well enough to be able to have a professional looking product. I work for a non-profit organization that relies on these kinds of presentations for fundraising. I will be filming indoors under a variety of light settings (florescent, incandescent), outdoors, etc. I will be recording kids singing and performing as well.

I have been told that I should get a camera that has user adjustable white balance. I also want one with a jack for an external mic and want mini dv format.

1. What other functions should I get?
2. What recommendations do you have for a used camera? I am hoping to get this "trial" camera for under $150. It is to be a learning and growing tool to not only learn how to use the various functions on the camera in a variety of light settings but also to come to my own conclusions about what I want/need and don't want/need.