Jürgen,
I would not buy a bike without riding it first - but at the same time would not buy a new bike either. There's too many good deals on used pro level equipment for the rec user. Where are you located? Checkout
Cycling Forums, a great site similar to this one but geared for cyclists.
I just sold my 2300 ($250 - Dura Ace upgraded but lots of miles) on
Craigs List, maybe you can find a bike local to you there. Also checkout the local cycling clubs - their racers are usually upgrading their gear every couple of years.