Rans Enduro Sport, Hase Kettweisel Tandem, Merin Bear Valley beater bike
I'm significantly older than you and I've got several bikes to choose from.
If I had to limit myself to one bike, it would be a road bike. If I were buying a new road bike for myself today, I think that I'd look at the bikes like the Trek Pilot that have higher handlebars. I like my handlebars to be around 1 or 2 inches lower than the saddle.
I just road my new Trek Pilot 2.1 for the first time today. It was my very first ride on a road bike. I will be 54 iyears old in another week. I have been riding a comfort bike for 6 months. Boy, the Trek is really smooth and fast! I was worried about the new riding position, but the Pilot's gemeotry was very good on my back. Also, I was afraid of the new seat. I am used to a large gel padded seat on my comfort bike, but my new raod bike has a Trek CRZ saddle with a cut-out channel. It is a small saddle compared to what I am used to riding. The new seat was great! I did not hurt at all.