Bike part list from best to worst Shimano

http://www.bikesportmichigan.com/features/dura-ace-ultegra.shtml

Dura Ace 7800
Dura Ace 7800 Triple
Dura Ace Track
Ultegra 6600 or 600
105 Silver
105 Black
Flat Bar
Tiagra
Sora
RX-100
RSX
C-Series
2203

Mountain:
Deore XTR
Deore XT
Deore LX /DX
100GS
STX /500GS
Saint135
Saint150
Hone
Deore
Alivio /400GS /Exage
Acera /300GS
Altus / 200GS
Tourney
Nexus

Shimano Dura-Ace 7800 Series for 2008 is Shimano’s highest-end component kit. It is the same kit that has won the Ford Ironman Triathlon World Championships and seven consecutive Tours de France on Lance Armstrong’s bike. When you consider Shimano’s market share versus Campagnolo and SRAM there is no doubt that, worldwide, Shimano Dura-Ace is the most winning component group on the planet.