I used to think I knew the answer to this one. 2-3 ft above ear level and dipoles for (older) DPL era soundtracks (with mostly ambience in the surrounds), but then maybe only 12" above ear level and direct radiators for more discrete (and newer) DD/DD EX/DTS/DTS-ES film scores with more spatially relevant elements in the back. That's the route I went, and I got to be honest, I feel the surrounds specifically (the rears are OK), have become too localizeable on some elements of some soundtracks. Becomes a distraction. The reason why I theoretically don't like dipoles, is the crappy on axis freq response, and the fact that if you put them 2-3 ft up, you get massively rolled off highs. But maybe that is exactly what you want for less localization? I'd be curious as to others' experience and specifcally if you've tried various types of speakers at different heights. Direct radiators 12" above work great for multichannel music, but not so great IMO for films. And one more (!) question is, OK, do I keep the monopoles and just raise them up, or potentially try bi/di/omni-poles and keep them at the same height. Or something in between?