From Ubuntu 10.10 (Maverick Meerkat) Shotwell is the new default photo manager.
I've tried it under Ubuntu 10.04 (Lucid Lynx) but, unfortunately, the latest version (0.7.2 at the time of writing) is not available so, without it, pictures could not be imported from F-spot and therefore you should re-add all metadata (eg: tags) once again.
Luckily, simply adding the right repository is enough to make the latest version available under Ubuntu 10.04 as well. To do that run the command:
sudo add-apt-repository ppa:yorba/ppa
update the source list:
sudo apt-get update
and install/upgrade it:
sudo apt-get install shotwell
Now in the menu "File" appears "Import from F-spot".
I've imported almost 10GB of photos with no problems.
Unique downside of Shotwell found out so far is that it doesn't support the organization of tags as a tree.
For example, I used to have a tag "England" which was the parent of "Manchester" and "London". This in Shotwell cannot be done. Pictures can have more than one tag though...
Well, give it a try and see if it suits your needs...