I'm a big classical fan,too and was a Chicago Symphony season subscriber for many years. ELP's classical leanings have excited me. I love Pictures, and their interpretations of Copland and Joplin on the Works albums.
Can't wait for Tarkus & Pictures in 5.1.
I must say that in some cases I don't even know whether I prefer the original classical versions themselves or what ELP did with them. For instance, I prefer ELP's Hoedown and Fanfare for the common man than the original versions by Copland (please forgive me the purists). But I can't decide between ELP's Canario and the "Canario" movement from "Fantasia para un gentilhombre" by Rodrigo.