What I have personally noticed in my years of playing that the only person really concerned with "The Key" of a song tends to be the guitar players since, we tend to think of the solos, ocassionally you will get the same concern from a singer but not as often as I would expect.

Usually as far as "key" or "chord names" go, I have found you just tend to stick with the generic, A,B,G (mostly for power chords while getting the songs down) the Minors, 7ths, susses etc. usually come after you have nailed the stucture down, and the bass player and drummer and singer usually care less.

This isn't always the case and sometimes if the other members have some music theory knowledge under their belt you find that discussions of "Key Changes" or finding the "right chord" for a song you are working on to be fun and helps create fresh ideas to either take the song in a different direction or help inspire new song ideas.

Pretty Much Gennation hit the nail on the head with his statement about -- Knowing enough Theory to be able to comunicate with other musicians. Or Basically the KISS method ( Keep It Simple Stupid ) so I would agree that just knowing the basic diatonic theory should allow you to comunicate and be understood as well as understand what is fundementaly "going on".

I haven't heard him in years (since Berklee) but wasn't Theloneous Monk another musician that played "outside of the box" alot in regards to the notes he used while playing and writing his jazz compositions?