Is it "cutting off" in the pattern when I go before a plane that is going faster than I am but let me in first? While turning from the 45˚ to the downwind leg for a downwind pattern landing in a Cessna 182, a Cheyenne was calling 5 miles out on a GPS approach for a straight in landing.  Clear day, both flying VFR, uncontrolled airport.  He and I had been communicating for 5-6 minutes, and I called my base turn knowing I had entered the pattern well ahead of him and had time to land ahead of him.  The Cheyenne pilot acknowledged me and was good with this.

Seconds before I touched down, I heard from a pilot evidently taxiing to take off from the same runway, "Dude ... you just cut off that Cheyenne ... you realize he's going about 4 times faster than you."

Now aside from his ignorance by not hearing the leadup conversation to our opposite direction approaches, when is a plane in a straight-on landing considered to have the right of way over one "in the pattern" and when, apart from communicating between pilots, is it proper regulation to land ahead, vs. extending the downwind leg and falling in behind him?

I was specifically trained that until you are within 4 miles, you are technically not on "final" during a straight-in approach ... but that common sense must prevail, so even if you reach the pattern first, it may be courteous and safer to allow a faster aircraft in ahead of you.
The Cheyenne would have been "cutting you off", if he hadn't worked it out with the aircraft in the pattern and maintained visual separation.

According to the AIM, 4-3-3, standard pattern entry at an uncontrolled airport is abeam the midpoint in the downwind. 


  
  Enter pattern in level flight, abeam the midpoint of the runway, at pattern altitude. (1,000’ AGL is recommended pattern altitude unless established otherwise. . .)
  


http://www.faraim.org/aim/aim-4-03-14-189.html