Started off with a D40 around a year ago, and I loved it! However, I feel like I would like the features of a D90 over what the D40 for the following reasons: - Exposure bracketing, I like doing HDR shots. - Better low light and ISO performance, I imagine the much higher ISO ranges in the D90 blows away the D40 (ISO 200/400/800 and the 1600 which is basically useless). I like low light pictures, long exposure photog as well - Higher megapixel resolution 6.1 vs 12.3 ... Noticed that when doing zoomed shots with my 500-200mm lens and doing some cropping, I would like more resolution, basically - Self sensor cleaning. It's a pain having to clean the D40s sensor so much, maybe I won't have to do this as often on the D90? - I'd like capability to shoot videos with it. Are my upgrade needs justified, or should I save my money and get a D5000 instead?