Overrated:
...Probably Mozart too, but I feel kind of dirty saying that. I do really love lots of his music, but I'm not sure he's as good as everyone says (personally, he doesn't hold a candle to Beethoven).
Underrated:
For me, I'm not sure I have one specific one, but it always strikes me how some of the unknown early Romantic composers I've heard have been forgotten. Hummel, I think, is fairly well known, but people like Carl Czerny or Ferdinand Ries (both protegees of Beethoven), or also Friedrich von Flotow seem to be cruely ignored, when, I think at least, some of their piano concertos etc are getting close to a par with Beethoven...or at least Schubert.
Example:
http://www.youtube.com/watch?v=kYbaG8AF ... re=relatedPretty emotional stuff....
