I play the classical guitar. There's a lot of reasons for this, and I'll try to explain some of them here. First, I'll talk about why I play my instrument, and then I'll talk about why I play music. Or maybe they'll end up all mixed up. Who knows?
Anyways. I have minor hearing problems (Minor. Right.) and I don't want to go deaf, so I chose an instrument that wasn't terribly loud. Nothing electric, and no drums. None of the wind instruments either, at least not the brass ones.
I like being able to play an instrument with my fingers, I don't like a bow, or keys between me and what's making the sound. That's not to say I don't like the piano or the cello or violin. I do. I have learned how to play the piano, and I think the cello would be fun if I had the time. But they're not my first choices because I'm not touching the strings.
This left me with only a few choices. I wanted something modern and very portable, something I could put in the car for road trips, and find people who play it, and music written for it. Thus, I chose the classical guitar. It fits all of these criteria.
With the guitar, you can produce, in my opinion, more timbres than any other instrument, more feelings for every note. This gives the guitar an incredible expressive range. And while it's a quiet instrument relatively, a good guitar can still fill a concert hall with no amplification. Yet it's still quiet enough to be played in an intimate living room, for a mere handful of people. I love the guitar because it is so versatile.
I love the classical guitar because it has an amazing repertoire. You can play Bach on it. (I do.) You can play Beatles. (I don't.) You can play some really fun new pieces that sound really cool (Villa Lobos and Andrew York spring to mind.), and also play music from several hundred years ago that, while transcribed, sounds like it fits the instrument. I love the guitar because of it's repertoire.
I chose the classical guitar, and I have never once regretted my choice. I love the instrument. As for why I play music, I suppose that's another post. I'll just say this here: Music is what emotions sound like.