Jupiter

Orbit Stablizer

Some have said the the Earth's orbit is so nice is because of Jupiter. Apparently, without Jupiter, the Earth's orbit would become highly eccentric and unstable. I don't know about that, but I'm willing to believe it.

Giant Meteor Vacuum

Jupiter's gravity deflects incoming meteors so they miss us, but it seems to me that it would also deflect those that would miss us in to hitting us. Perhaps it's in the percentages, more deflects to miss than hits. Anyway, any meteor that strikes Jupiter will miss the Earth. Jupiter (and the other giants) are taking hits even now. We all remember the Shumaker-Levy 9 comet, right?