Well it's been a month since my last coffee and I don't think I'll go back to any sort of regular intake.
I'm actually quite surprised at the difference it has made. My mind feels clearer even when I'm not 100%. My tiredness levels are no worse, and best of all I no longer suffer from the buzzy heights and groggy depths of the caffeine roller-coaster - my alertness now follows a much smoother gradient.
That being said though, I will still happily enjoy the odd cup every now and then, just never again in the regular quantities I did in the past.