I serve at a small Episcopal Church that tends to be very "high Church" for the Sunday Mass. I receive my Communion right after the Priest (along with the Deacon, Chalice Bearer, and Server) which allows me time to get back to the organ and start my piece before the congregation gets to the rail.
I found a long time ago that I always seem to get compliments when I select a hymn tune that the congregation recognizes. Sometimes, if Communion is taking longer than usual, I will work my way up or down into a different key, or improvise my way into an entirely different hymn tune. I play quietly and use a registration with a flute celeste until the congregation has finished. Once the congregation has been seated, I draw one or two brighter stops on the swell and add a 16' to the pedal, all the while keeping an eye on the Priest so I can finish up right after he gets the Altar table back in order.
I have never tried to "show out" while playing during the Eucharist, nor the Prelude or Offertory for that matter. The only time I feel it appropriate to "perform" (for lack of a better word) is the Postlude. For that, I let 'er rip!
David