Well, I used to wear mine really high... as high as my strap would allow. (Well, I still wear one of my straps as high as it can allow, but it's just longer than my other straps.) But after I saw some pictures of myself wearing the bass so high, I realized three things:
1. I look like a total goober.
2. My plucking wrist was bent at an unhealthy angle which could possibly end with tendonitis or other such problems.
3. I couldn't really move or "rock out," which can be important sometimes.
So I decided to let out some slack and wear it lower. Now it sits over my stomach. Still pretty high, but low enough to allow still good access to the all the upper frets while keeping my plucking hand (and wrist) in a more natural and comfortable position. Also, I can now move more easily and dance a little as I jam.
However when anyone else tries my basses on, they almost invariably say it's too high for them.