Phil's Rambling Rants
My understanding is that paper transmission is better than e-mail. I've also been told that faxes are better than mail, since they arrive significantly faster (there is still a hold up in delivery of physical mail, I understand, because of the procedures instituted after the anthrax scares).
With respect to other methods that require more commitment, a group will get more attention from staff people and the the representative or senator than a single individual. If there are several people who are interested in the same topic, try to attend as a group at town hall meetings and other events where the elected official or one of their staff members will be present. Subscribe to the official's electronic or hard copy news letter to learn about opportunities to interact. Call the office and ask for the name of the staff member supervising constituent relations for your area. Seek opportunities to build relationships.
Just my $.02