I have to pick Seventh Wonder, but what an incredible field we had this year.
Accept would be my pick if Thursday was included. Best show of the weekend, and this is from someone who has only casually listened to them over the last year and may have heard a song here or there before that.
Kamelot almost shouldn't count. It was that good and that special. Sidenote: we convinced two friends to come this year, and their primary reason was Kamelot. They were bummed about Roy. When the curtain closed, they both agreed it was the best show they had ever seen in their lives.
Leprous was also fantastic on Thursday, and DGM (they had been my most anticipated as of the announcement a year ago) were great as well.
Delain was awesome too, and I really enjoyed most of the other bands that I haven't mentioned. Not a Blackguard fan, couldn't get into OoS (this may have been a combination of unfamiliarity, the unbearable heat, and how far I was sitting), and I am really bummed we got stuck at the Vortex and didn't make it back in time for Stormwarrior as I had been looking forward to them. The great food and cheap gold label may just have been worth it though.