I own and play electric and accoustic guitar, electric and accoustic bass,mandolin,electric violin, harmonica, tin whistle, drums.
But I suck with anything that use a keyboard.
I picked up the bass first, because my friends in high school had a band, and I wanted to join one. Bassist was the least popular choice, so there was more demand for one.
I learned guitar after, because it's more fun when playing alone.
The mandolin, tin whistle and harmonica were a result of my discovery of the Pogues.
The violin is a gift. I'm not very good with it, and I don't practice much, it's not as rewarding as the other ones.
The drums because it's fun, and it complete my one-man-band setup.
I never liked the piano much. I like the sound and the music made for it, but not the context needed to play:
Piano is a big, expensive instrument, and people come to you to listen to you playing.
Guitar is light and unexpensive, and you bring it with you to play for others.
Now, I know there are lighter synths that you can carry under your arm, but come on, how many campfire song have you seen played on a keybord?
Or maybe I'm just frustrated over my inability to play a scale on a keyboard without tangling my fingers together.