If considering steel, the 2010,11 or12 Specialized Allez Steel Double (Triple if you can find one) has already done the hard work of making 70's/80's steel geometry and feel, work with modern wheel sizes and A-headsets and dual pivot sidepulls etc. I hear people have bought them new for $399 but they retail for ~$750. Nashbar and Fuji both make retro-style steel steeds with 21st Century braking and shifting hardware in the $399 t0 $599 price range.

H