I too use a lot of stills in docs. Sometimes it's better to put all your stills on one timeline and export them as one video. Then use the video when editing. If they're physical images, then scanning would yield the best results probably.
Other times, you might want to film them, a la "Dog Town N Z-Boys" (see it if you haven't)
Here's an example of stills being used in may different ways:
http://vimeo.com/1081535