I missed my plagued drake by one achievement (3D). You better believe I tried desperately with all my might the weeks before Ulduar came out to get it. But no, my guild could only pull together one successful 3D run beforehand, and I wasn't in it. :-\
After that run, none of the people who were in it felt much like going back, which was a real downer, but I can't blame them. They worked on the fight for 5 hours before they finally got it. They got real burned out on it.
My consolation prize was getting the Azure Drake a few weeks after Ulduar came out. Sure it wasn't a "badge of honor" like the plagued drake was, but I loved it (and still do).