What irony? Sony and MS always have good shows compared to Nintendo's snoozefests. I'm perfectly aware that Sony fans are easily the majority here, which is why they're winning, but seeing Nintendo win over MS is just funny and I have to make that remark.
This gen Sony's pretty much bombed at every E3 until last year. Nintendo ruled 2006 though, but their 2008 conference was probably the worst for any platform holder this generation, and 2009 (despite attractive content) still fell flat. The only company who has consistently good shows is Microsoft, and a lot of that has to do with their top notch stagecraft and presentation.
"Winning" E3 seems like a pretty hollow achievement anyway. Sega invariably used to "win" and look where they are now...