The best beer I've ever brewed was a batch of my None More Black IPA nearly two years ago. It was the first batch of 2011. Just had something about it that I haven't quite been able to duplicate; I'm pretty close, but not quite.
I'm definitely not one of those who feels it was the next one or the last one I brewed. I'm waaaaay too picky with my beer. It has to be what I'm wanting for it to be good. My palate changes too much, I think.
I should also say that I'm way more critical of my beer than I'd like to be. Seems like a lot of you guys like your beer no matter what flaws it may have. For me, if it is anything short of super tasty, I get down on myself. I need to lay off that a little, I think. I get caught up in trying to create beer that is as good as the stuff I can buy in the stores. I think it should be. But when it's not, I start questioning myself, second guessing my ability, it's upsetting.