Don't feel bad about having a Xenar, great lens with a really nice look. The Xenotar and Planars are really only better at the wide apertures. The main reason for getting a 'Flex over a 'Cord is the wonderful automatic feed, better viewfinder and having the focus know on the correct side!
The later model Rollei T is a good budget alternative to a full blown F, and the Tessar on those is a truly great lens.