In addition to the "Camera timer for taking timed shots" brainstorm, I miss another feature I used to have in my ancient Nokia N80. There seems no possibility to take more than one photo at a time. Each picture needs separate user action.
Doing a series of shots has some advantages when for example taking group photos. Multiple photos higher your chances of having at least one suitable shot where nobody looks dumb like a brick ;)
Also, when observing things, a "series of shots" feature with a larger time between the individual photos saves you some effort. Another point is that the photos are perfectly aligned at the same point of interest, because no one needs to touch the N900. This offers the possibility of creating time-lapse images.
Well, and the final evolution stage of such a feature could be a series of photos with programmable settings for each picture. Combining it with small delays will then be enough to create the raw material for HDR images.