As a kid, the instrument I was most drawn to was drums, but there was no way my parents were having that (plus I had to save my own money to buy my first cheapo bass... an entire drumkit wouldn't have been affordable). I think I could have been a better drummer than bass player because rhythm just comes naturally to me. But, at the same time, I'm not sure that that would be my answer now because I would be missing out on the melodic/harmonic aspects of music.
In a practical sense, I would say piano, simply because I think it gives you the entire musical picture (basslines, chords, melody, harmony). You can accompany yourself, and the theory is really laid out in front of your eyes.
But, from simply a, "That's an awesome sound" point of view, I think I would lean towards trumpet.
But at the end of the day, I was meant to be a bass player, and I'm happy with it!
