What Are Your Favorite Instrumental Tunes?

The subject of instrumentals came up in another thread, so I thought it might be fun to see what instrumental tunes everyone enjoys. Instrumentals cover a wide range of genres when you start to think about it; classical (of course), movie soundtracks, pop, jazz, big band oldies, blues, country, rock, and many instrumental versions of your favorite song titles, too.

So what instrumental music do you like? What are your favorite tunes or instrumental versions of your favorite songs? Multiple tunes and multiple genres are okay. And, if you have favorite on youtube, feel free to post the link so that we can listen, too!