i would say try and go for at least a 2 series if you go trek. or try and go at least $1k plus if you go other brands. you get a lot more bike for less money.

at the same time though, i have heard a story of a guy who had a trek 1.1 and was just crushing souls on a group ride. so its all in the rider and what you think you will want. basically if you get the 1 series it can last you, but if you're the type of person who likes having more than they need for some room to grow, you wont be disappointed if you spend a lil more.