Carbon fork = ~$500
Caliper Brake = ~$100
New Wheelset = ~$450 - $600 (Rolf's @ $950, Topolinos @ $1,200: neither are user servicable)
New Crankset = ~$500
New Bits & Pieces = ~$400

It all adds up... however, in reading the OP's postings he's obviously dropped a few bucks on bikes and components over the years and should have a full appreciation for what the costs of an upgrade would be.