When I tried to convince somebody to try Ubuntu, he tells me "OK, but I need to import my pictures, with the preferences I have entered on Windows Gallery (tags, and marks). I have a lot of pictures on my computer, and I have spend lot of time to organize them."
I checked this option on F-Spot and I didn't find anything to do this. This could be a good idea to help Windows' users (and why not MAC OS' users which I don't really know) to migrate under Ubuntu (Linux in general).
I know that this should not be a priority for the community, but if it interest a developer, I am pretty sure that this option will be very useful.