Look around for a pull-off group.
My first road bike was a Trek 1.2 with Sora/2300. Once I got the Giant TCR Composite, I relegated the Trek to rollers/trainer duty. Then I got a powertap and wanted to have power during indoor training.
I got lucky when a guy at my LBS was selling a complete 105-5700 group as a pull-off for _CHEAP_. Now my Trek is 105s with 10-speed.
I like my Trek well enough that I ride it outdoors every so often and enjoy it. I even put aero-bars on it for my local weekly TT.