Having aquired a very nice new SLR just before Christmas, I seriously considered doing this. But the sense of disappointment I'd feel in myself from the inevitable missed day means I've just decided to take as many photos as I can every week, just because.
What I've learned from looking at all the amazing photos people have posted on Flickr is that you don't need a reason to make an image, just as long as it pleases you. It's like any other kind of art - you've got to practice, innit?