I am selling my upgraded Giant road bike for $550. I used it for my daily commutes which were also my training sessions (10 - 12 miles one way). The frame is a 56 cm Giant Defy (2011). I am 6' tall and it was OK, but I think it would be perfect for people between 5.6' and 5.9'. It is made of Giant's high end aluminum ALUXX-SL. The fork is composite. Everything else on this bike was replaced by the following parts:

Ultegra crankset, 9-speed, 172.5 mm, compact 50/34 (perfect for mountains!), Hollowtech
Ultegra shift/brake levers
Ultegra brakes
Ultegra Front Derailleur (Braze-on)
Dura-Ace Rear Derailleur
Dura-Ace bottom bracket
SRAM PG970 9-speed cassette (12/26)
SRAM PG971 chain
Cinelli handlebar with SRAM supercork bar tape
Ritchey Pro stem
Avenir 300 Series ROAD Saddle
Shimano WH-R501-A wheelset (700 cc) (very reliable and will run forever without problems)
Specialized Turbo Elite tires (23 mm)

Since this was a commuter bike it comes with some special features:

Planet Bike 7058 Cascadia Fender Set which can be easily taken off if you want to use the bike only for training sessions.
Shimano A530 SPD hybrid pedals can be used with normal shoes or attachable mountain bike/casual cycling shoes which are more comfortable for walking than road bike shoes (which work too with the right cleats).
Lock holder can be taken off, but I will add a free Kryptonite lock to this offer just in case as well as a free pump.

I am selling the bike because my daily commute became too long for a bike ride after I moved. The bike has some superficial scratches, but it runs just fine. The Ultegra/Dura-Ace groupset is known for its performance and durability, is well maintained and was professionally installed by a pro bike shop. Please contact me if you want to check out the bike for a ride.