You awake one night to find a magical being standing over you. He offers you a power, the ability to play one instrument better than anyone else in the world, but if you play for anyone other than yourself you lose the ability to play any instrument. What instrument would you pick?

I'd pick the banjo, seems like something fun to play while sitting alone in a rocking chair.

The Accordian

http://www.quickmeme.com/img/02/029f931802f33da9e44ba7017391ef12cc7523a129aad5cd3666cb8ac9617e48.jpg

The ability to play a musical instrument in and of itself isn't nearly enough to guarantee wealth anyway, so the downside isn't much of one. Of course what if someone hears you but you aren't playing for them? for example you live in an apartment with thin walls?

My instrument in any case would have to be the kazoo.

What's the point of playing instruments if you can't even pick up the females with your skillz?

Anyway...Theremin. No question.

If someone just happens to hear you it's ok. As long as you aren't specifically playing for someone to hear. Note this can't be exploited in ways like "I'm sitting in this town square playing for myself and everyone else may happen to hear it."

Hmmmm, I don't see the point really. I mean I enjoy music, but I enjoy sharing music, I enjoy playing the drums, but that would for sure be an instrument that is super boring to play alone.

Maybe some weird intrument like the digeridoo or the mouth harp.

Ocarina, LET IT RAIN [censored]ES!

I'd refuse, part of the fun is learning and it would be pointless not to be able to play for others.

What about recording yourself playing for yourself and then sending someone the tape?

Saxophone. Refer to men at work as to the reason why

Holophonor.

The violin I always loved the sound of the violin. The only other instrument that I like the sound of more is an acoustic guitar but I can already play it very well.

The computer, have you hear the dubstep that thing can make?

The Piano!

Well, since you sent the tape to someone with the intent for them to listen to it, that'd be bad.

How does the being know?

If the being is powerful enough to do that, why does it care so much?

The bagpipe.

the http://en.wikipedia.org/wiki/Theremin

Oh damn I forgot the bagpipes! My brother is going to kill me. (He lives in Scotland and has barely any Scottish blood but he associates himself as 100% Scottish.)

I already play the banjo in front of people. Better than anyone else in the world? Why? Much more fun being average and having the craic. Gonna have to come up with a much better offer. Never playing for anyone else again would require, at the very least, a habitable planet of my very own and God-level insights into symmetry splitting and the unified field. And drink.

http://en.wikipedia.org/wiki/Venu. I've always enjoyed listening to it.

Better than anyone in the world, but no one can hear your performances? In this scenario I couldn't care less if I'm the world's best. (For that matter, being absolute best wouldn't matter to me even if I could be heard by others.) I'd settle for being able to perform any and all music of my choosing up to a level of musicality and technical prowess that satisfies me.

At first I was gonna say it would have to be an instrument that doesn't require user manipulation to play in tune during performance, since my hearing isn't the best in that regard. But...can we assume that part of the deal is that we'd end up with perfect pitch and excellent hearing? I could go the other way and say it doesn't matter if one plays out of tune since the player won't know the difference and no one who does will ever hear him or her. But going this route contradicts being "best".

All that aside, I'd likely pick concert grand piano. It has by far the widest selection of solo literature from the musical eras I'm interested in, including transcriptions of works originally written for ensembles of various sizes. I could thus play, say, not only all the Beethoven piano sonatas but also his symphonies in piano reduction.

Seems like a trick to me, I would inquire if my skill would actually get better or if everyone else in the world would just become worse than myself. I mean, this magical creature decides to wake up me in the sanctity of my home to offer me some mysterious gift without even introducing themselves or have any known background on the "person"?

That just seems shady to me.

Anyways, I would probably just pick the guitar.

Classical guitar. Plus, the skill in being able to play it to that level would no doubt transfer across to acoustic and electric guitars which hopefully here are classed as different instruments so could be played with other people.

That or the piano for similar reasons. Not that keen on the piano sound per se but like organs, harpsichords and synth keyboards.

Electric Guitar.

Holy [censored] the solos I'd be enjoying myself with. Ah...