The attic offers important opportunities to make energy saving improvements.
Add wall, ceiling and duct insulation when remodeling and opening walls.
Seal air leaks around doors, windows, electrical outlets.
This US Department of Energy tool will give you zip code specific information on insulation: www.ornl.gov/~roofs/Zip/ZipHome.html
US Department of Energy tips on adding insulation to an existing home: www.ornl.gov/sci/roofs+walls/insulation/ins_06.html