Do we need all the mega pixels to create interesting photos? I believe not. But having fewer mega pixels at our disposal requires carefull planning while composing your shot, as you don't want to loose "pixel real estate" by cropping in post processing. I own a Nikon D300 with a 12 Mp sensor and it has served me well for 4 years. As I grew up shooting film I'm used to think all aspects through before capturing the actual photo and thereby keeping post processing to a minimum. But a Nikon D800 is on its way to me as the extra "pixel real estate" of a 36 Mp sensor offers a large freedom to crop interesting parts of photo.
Take this photo as an example. I used my Nikon D300 with a Sigma 70-200 f/2.8 and walked to a nearby creek. The I sad down on a small canoe gangway and looked at the scene around me for nearly 20 minuttes before a photo took form in my mind. The photo was composed so cropping would not necessary. The still water entering a large area of rush that took the form a great wall, looked like a potential interesting scene if transformed with one of my own texture layers and post processed in CS6.