I love openings and endings!
I actually love it when little bits of information are buried in there, so you see it later and you think, "How did I miss that!?"
I love seeing the animation with the music, too.
Best thing that a show has done with an opening? Watch season 2 of Love Live. It's wonderful. It's one of those, "if you weren't crying already..." moments.
Also this -> https://youtu.be/osKkMKolWQ8?t=1m6s.
Find Suzaku in that part.
As a song, I really love the ending of the last episode of season 1 of K, "To Be With U". I love the season 1 OP, too, but I think I like "To Be With U" a little bit more. Especially if you play it right after "Requiem of Red".
(Also if you haven't watched Love Live and K, go watch them because they're amazing shows.)