I will be blunt. You NEED to try some bikes out. No way around it. A good LBS will accommodate you! Even if you have to travel to a nearby city to try them out, please make that trip.

Get a bike that is comfortable and don't worry about the geometry ("aggressive" or whatever). You will be the fastest and strongest rider you can be if your bike fits YOU properly. Bikes that look fast but don't fit are no fun to ride.