For commuting I personally like the simplest possible "flat-bar road bike" format with V-brakes and either trigger shifters or Grip Shifts. Simple old-style non-suspension mountain bikes are also good, provided the frame actually fits you. (so many don't) I did the bmx/mtb commuting for a decade too, until moving to a hilly place forced me to move to a road bike.

Handlebars, shifters and brakes are a highly personal choice. If you prefer what people call "drop" handlebars I'd suggest a "touring" bike instead of a "cyclocross". The "touring" setup typically has more mounting points and area for fenders and gear, a longer wheelbase, and in particular a longer chainstay for mounting racks in back. These labels tend to be driven more by fashion and marketing than anything else, so each company willl outfit their models differently.