[Ceriopal]

Mines either Rachmaninoff's Op.3 No.2 - Prelude in C# Minor

http://www.icarus3.com/av/rachprelude.html

or Beethoven's Moonlight Sonata - well the first movement at least.

http://youtube.com/watch?v=vQVeaIHWWck

[JohnfAclambrJA]

Well it's more jazz/classical..but the koln concert by keith jarrett is probably the best piano piece i've ever heard.

I think i've listened to it at least 500x (seriously)

edit:
or Beethoven's Moonlight Sonata - well the first movement at least. moonlight 3rd mov is also nice imo, well to play

[Gaxiciverfere]

Hard to pick a favorite, but if I had to I would say almost all of Mozart's Requiem is good mainly because of the story of the piece and its creation. But if I had to pick a movement from that piece it would have to be the 3rd movement specifically the Confutatis section. Followed closely by the famous Dies Irae section.

Confutatis:

http://www.youtube.com/watch?v=tXXHYX7zk1c

Dies Irae:

http://www.youtube.com/watch?v=M_YSEbAWA0Y

[DoctorAlexandro]

I'm a sucker for anything Mozart or Beethoven. I don't think I could pick just one... [surrender]

[DoctorBretonDen]

Gabriel's Oboe, From The Mission

http://youtube.com/watch?v=PRb8KKyenSY

[paratayoma]

Fille aux Cheveux de lin by Claude Debussy. You'll also find some very good string versions of it, one in particular by Joshua Bell.