Really, this was probably the best season finale I've seen. Seriously, it had everything. Maybe it wasn't the funniest episode, but storywise, don't think so many others can beat this one. I mean, Lily getting pregnant, the destruction of The Arcadian, and was I the only one who thought the girl that incidentally got the flower was really the Mother? And, ofcourse, the (perhaps) most obvious, and awesome, part. Barney. Stinson. Getting married. Now only thing that matters until at least September is, who? For me, I believe it's Nora, because Robin has something going on with her secret crush, too, and well, Nora seems to fit better, in my opinion. The only bad thing about Challenge Accepted was that even though it answered a lot of questions, it gave so many new ones, that might not be answered too soon.
And also, I apologize (mostly to JediRouge and blind.bandit), I haven't been able to edit so much lately, and it might continue like that for like a month, because I'm soo busy in school.