The Gold Circle was reserved for AOL, Nokia, O2 and other corporate clients who had put up the money to pay for the show. Presumably this was the carrot that persuaded them to throw so much cash at it at such short notice. Tickets for this area were available for as much as £600 only for these companies.
I was around 10 yards behind the Gold Circle in the front of the packed area reserved for the "common folk", which, let's face it, was around 140,000 of the audience. It was rather galling to see later, on video, just how much space there was in the privileged area, given how tight it was just behind it. Still, I would rather have been there than not at all. But one is left with the impression that the rest of the audience were allowed in not just to watch the show, but to watch those in the Golden Circle have a good time.
You are quite right, there were too many good performances for a standout to appear obvious on television, but to those actually in Hyde Park it was clear that Robbie Williams was the favourite. Although Pink Floyd received a great reception for an incredibly moving set (it brought tears to the eyes of many, and for the right reasons), this was purely amongst those who had decided to stay after Robbie.
I honestly cannot believe that I saw the full Pink Floyd lineup - I never thought I would live to see the day. Although it is highly unlikely that it will ever lead to anything other than happy memories, at least they did it like they said they would, and that's that. I have already watched the video several times - it is easily Floyd's greatest gig already (in spite of noticeable cock-ups by all band members except Rick Wright). To hear Roger Waters sing the second verse of Wish You Were Here was a revelation. This picture below is from the Brain Damage Fansite: