This is a great topic!
During my time in Corporate America [GM & Black & Decker], a title was your ticket to acceptance at various levels. Without it you held no power, no ability to prompt change and generally no voice either (unless you were in a brainstorm or VOC session, where everyone was equal). In my case, as my responsibilities grew to different continents it would have been impossible to lead the 3 office group without that title in my email signature. It was all about structure - pay grade, vacation, comps, bonuses - without the titles it would have been chaos. All the while, the titles were also a hindrance, a way to get-off-the-hook for decisions and actions - a ticket to look to someone higher for the hard decisions. So that ole adage of why Corporate America is broken seemed to shined brightly at both of those companies. A friend worked at CAT and told me that everyone except Presidents of their divisions are titled ‘Manager’. I guess that makes some sense, we all manage something! There’s a leader of a large, softsewn company we dealt with in Mexico whose card reads, "Head Honcho’. I’ve always gotten a chuckle from his card.
NURB, I admire your office situation - everyone must feel empowered and able to facilitate change / voice an opinion (or at least I hope so 
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As for now, the title doesn’t mean anything to me - we’re structured as a team and I consider everyone on our team a Partner. It’s more for clients and my business card than anything else.