Did you know that jupter is a star that failed? If it was more massive, it would have becoming hot enough to start nuclear fusion in it's core, and our solar system would have become a binary system.
I watched a really good show recently about the solar system and it's origin. It was up to date...this year I think. Fascinating stuff. I can't wait to see what future telescopes will bring.
That is due to Jupiter's deep gravity well, which also is useful for speeding up satellites and probes destined for outer planets or beyond with the sling shot method.