My little Malvern Star Flite project is stripped back to frame only (http://www.flickr.com/photos/theflite/).
For interest's sake, I weighed almost everything when I removed it.
Frame (steel, hi-ten) - 2.8kg
Fork (steel, hi-ten) - 865g
Rear wheel with 5 speed cassette (steel 27" rim, original Panaracer 1 1/4 tyres) - 2.75kg
Front wheel (rim and tyre same as rear) - 2.05kg
Handlebar and stem (Alps) - 955g
Rear derailleur (Shimano Skylark) - 280g
Front derailler (Shimano) - 150g
Cranks, pedals and toe clips (Sugino 52/42 cranks) - 1.54kg
Seat and seat post - 675g
Front and rear brake calipers (Shimano Tourney) - 300g
Stem shifters (Shimano) - 80g
Brake levers (Shimano) - 270g
Chain - didn't weigh it.
Cables - didn't weigh them.
Headset - didn't weigh it.
Bottom bracket - didn't weigh it.
Total = 12.715kg (28lbs) plus an estimated additional 600g for the bits I didn't weigh, so call it 13.3kg (29lbs)
To a newbie bike restorer/rebirther like me it's interesting to see where all the weight is.