A mate of mine took me as a guest a week or so ago to a long-disused gravel pit, lined with mature overhanging trees and lily beds, shallow bars and distant depths and occasionally deep margins, where we shared an all float-caught catch of 12 tench and 1 large bream. I mentioned to him as we were leaving that it had been one of my favourite fishing sessions ever.
Why? Well, for one thing the surroundings were lovely. For another, save for one gentleman carp fishing on the other bank (who was packing up from his overnighter as we arrived) we had the place to ourselves. Another aspect was the quality of the fish - beautiful deep green tench up to just shy of 6 pounds. And lastly, for all our angling efforts, the fish didn't exactly throw themselves on to the hook, there was a real sense of effort vs reward, of feeling that you had achieved something good, but equally that you could have achieved more.
So that's a long way of saying - my favourite venue has those qualities mentioned by some other, relative solitude, natural beauty, a quarry worth pursuing... but it would also be the venue from which I walk away from after fishing with a smile on my face for my successes and a puzzle in my head for my failures whilst already planning my return.