Mountain View = mediocre bike shops (no high-end stuff): Performance, the Off-Ramp (Fuji/Giant).
Los Altos = a few shops: that triathelete shop on El Camino, Chain Reaction by Foothill Expressway
Palo Alto = $$$$ bike shops: Palo Alto Bicycles, VeloTech on Emerson Street (BMC's, Pinarellos, deRosa, Pegoretti, Trek Madone, Look, Calfee, Parlee, etc). Be prepared to spend $5k-$10k+ though.
for mid-range carbon roadbikes, go to Mike's Bikes or Bike Connection in Palo Alto or Go-Ride in Redwood City, you can get a Specialized Tarmac/Roubaix or Cannondale Synapse or Scott or Felt F1series around $2k+