My Triathlon bike (early 90's) was the Trek 2300 with the carbon frame. It was extremely light and it really helped, specially in hilly terrain. Whatever your choices are, get the lightest and with the best components. And don't settle for a cheap one. Talk to other triathletes. In fact you should shop at a Triathlete store (if there is one in your area) instead of a Bike store. Miss my olympic distance triathlon days.