for me , its not about the quantity of coffee but the quality of coffee you drink.
coffee geek, or coffee nerd. Both of which are spoken with the highest respect and love. :)
I'll go waaaaay out on a limb here, but I usually just call them by their first name.
After brainstorming with a few 'coffee geek' friends, I find that 'coffee connoisseurs' sounds classy. Don't you think? I'm open to some other ideas, though.
It's a tough call between "brother" and "whiney bastard". Depends on the case I suppose.