Can anyone recommend a B&W film that retains good detail and gives true, rich, deep blacks? On the scale of flat to contrasty, my preference is more towards the contrasty side.
Speed isn't a factor as I'm usually working on a tripod.
Needs to be available in 120 size and currently produced.
Thanks in advance for sharing your experience,
Mark
You seem to be asking for two different (some might say "entirely opposite") things.
By definition, a film that naturally retains detail "well" in the high and low end in your average-contrast composition is not going to be a super contrasty film. The same things that cause a film to retain detail well in the high and low end are the things that make a film something other than a high-contrast film.
If you mean that you still want punch in the mid tones while having a good deal of printable detail in the low and high end, I would say that a "modern" emulsion would be your best bet, as they tend to have a bit less "sag" in the graph of the low end of their tonal rendering, and on the high end, hold tons of printable detail on a long straight[ish] line. Strictly technically speaking, something "T grained," like T-Max, Neopan, or Ilford Delta would be a good choice.
Non technically speaking, I usually prefer the way non-T-grained films react to light and shooting/processing tweaks (tonality), and the way they render grain and detail on the print (or, rather, they way they don't render, in the case of detail). I would personally use FP4 or Plus X. They have plenty of malleability and versatility, and are just plain gorgeous IMHO.
This is all assuming that you know what you are doing with a light meter, and understand how to shoot, process, and print to manipulate the picture, of course.

These are the most important things, by far.