If you're finished with putting the kids through college and your mortgage is paid off, then go with a very nice first bike and anticipate that you might buy another one soon afterwards.

Frame and components matter. Get a very good frameset and at least Ultegra. Then later get a custom wheelset. Bike fit is extremely important but the trouble is that its a dynamic process. There are intermediate steps as you get accustomed to riding a road bike. I chose to go to an independent fitter.