Cannondale, which built its reputation on top-end aluminum bikes, debuted its first all-carbon frame just three years ago. Fortunately, the company hasn't forgotten its roots. By marrying a carbon front triangle (the top tube, head tube, and down tube) to an aerospace-grade-aluminum rear triangle (everything else), Cannondale delivers the best of both worlds. Up front, the SystemSix's oversize carbon tubes deliver strength where it's neededin the bottom bracketwhile tuning out road chatter. In back, aluminum stays transfer every muscle twitch to the rear wheel. And, at just 16.5 pounds, it weighs less than bikes that cost twice as much. 16.5 lbs, 56 cm; cannondale.comBonus: This frame, this price, and you still get Mavic Ksyrium Elite wheels and a Dura-Ace/Ultegra mix.Bummer: The stays are as comfortable as aluminum gets, but you'll still feel every pebble.