I'd like to get some weight saving in, but atm I think it's going to be drivetrain. The chain is knackered, bb/crank are creaking (they did this years ago, which was solved with new bolts, but that's not working anymore...), and the jockey wheels in the mech are knackered. The only bits I'd keep would be shifters, front mech (since it's bottom pull on a large seat tube size) and cassette (which is newer than the rest from when I changed to 8sp).