Use the geometry of your old bike as a baseline (assuming you are happy with fit there).

The geometry of the 08 version is here: http://www.giant-bicycles.com/en-US/...llections_id=3

Drop bars make the reach a little longer than most flat bars, so you may wan to go slightly shorter on the top tube.

Your best bet is to use the above geometry ("size" and effective top tube length mainly) to weed out bikes and then shop locally so you can still go try them out and confirm fit.