Originally Posted by
Jynx
Shifters - Spend your money here. Ultegra or Dura Ace.
Rear Derailler - Spend your money here. Ultegra or Dura Ace.
Crank - Spend your money here. Ultegra or Dura Ace.
Brakes - Spend your money here. Ultegra or Dura Ace.
Front Derailler - Cheap out here. Tiagra
Chain - Cheap out here. 105
Cassette - Cheap out here. 105
Bottom Bracket - They are all similar prices. Just go with Dura Ace.
Just my opinion, but I don't think Dura-Ace is ever the answer when trying to shave a few dollars. I'd think a full Ultegra/105 bike would be just fine for just about anyone, and those that need more wouldn't need this discussion.
For a casual rider, I suggest mid-range on just about the entire drivetrain- Tiagra or 105 throughout; spend a little extra on the rear derailer. Stick with 9-speed for a while longer. I'm happier with SRAM cassettes and chains. I like campy square-taper cranks (their low-end bbs are fantastic).