It's a subject for a whole new thread I know - and it's probably already been done - but seems to me that bass playing height / playing stance goes very much with era and musical fashion:
In the 1960's it was as the John Entwhistle pic in posts above: standing fairly stationary (unless you were Jet Harris) with bass at mid-height, and plunking away (though of course JE took the plunking to a whole new level)
In the 1970's the rockers started slinging the bass l-o-o-o-w (as Pete Way, and also most of the punk rockers) plus adoption of the "power stance" and / or prowling about on stage (Phil Lynott, Chris Squire etc etc)
In the 1980's bass playing height either got even lower (hair metal), or if you were a funkster the bass was up under your armpit (as Mr Mark King - no Thunderbird pictured of course, but definitely a Thunderthumb...)
After that - anything goes.......