Sweet. Thanks for the replies, guys! I've been looking around more myself, and in addition to these comments, I think I've settled on the 4500. My only reservation is the sudden changes you were describing, sgspirit. The idea of having that problem really irks me. Does it happen a lot or what? Hrrmmmm...... :-?
It doesn't happen in settings where the scene is relatively evenly bright and colored. But if you're, say, panning from a dark forest to a bright area of water, it will suddenly auto-adjust for the change. Likewise, the DV-4500 has a control to change the zone the camera uses to set the brightness. It also uses that area to set the type of light (fluorescent, dim daylight, sunlight etc.). If you change the zone while filming, the new area the camera uses to evaluate the light conditions can change, and the camera can respond inappropriately. This is kind of hard to explain, but the newer cameras are much more intelligent in this sense, making fewer changes and doing them gradually.