Originally Posted by WebEffect
The direct radiating speakers create a LESS full sound, while the others create a more theatre-like sound.
I disagree with that statement. Monopoles create a very full sound but, due to their specific and defined radiation pattern, are more critical to set up and will suffer if placed inappropriately. Dipole/bipole surrounds bounce their radiations off the room surfaces and the sound arrives at the listening position from many directions, resulting in the impression of a diffuse source. This results in somewhat less specificity of source direction but a much greater tolerance for less than critical placement. If you look at the many threads here on setup and speaker placement, it will be apparent that many, if not most, posters cannot place all their speakers exactly where they should be and, therefore, benefit greatly from using bipole/dipole surrounds. In fact, I see no down-side to it for HT, at all. (Discrete multichannel music, of course, is another story.)
BTW, all the speakers you are referring to are 'direct radiators. The only common non-direct radiators are those with horn-loading or quarter-wave pipes.