Definately consider LWB (long wheel base) recumbents. They are great for middle aged guys like you and me. The upright seating position gets rid of a lot of bike related pain. Sun EZSport ($900-1300) Rans Stratus ($1700 +) and Easy Racers Tour Easy (2K +). All three are good bikes, but more dinero does mean a better bike.

As you age, the less you are willing to tolerate pain from fitting your body to the bike instead of fitting the bike to your body. LWB's are Zen. bk