Surrounds - Bipole, Dipole, or Direct

I am considering purchasing surround speakers and have heard differing opinions as to what are best - bipole, dipole, or direct radiating. Which do you prefer and why? Also, what surrounds do you like for $1000 - $1500? Thanks in advance.
Most "rear channel" speakers I have found have both a Dipole and Bipole mode. Which one suits you best will have to do with your room acoustics, and the relationship between you and speaker placement (i.e. behind you, directly to the side etc.) In my experience, these type speakers have a great advantage over a "direct radiating" type for surround applications. Set up correctly, they will vanish and all you will hear are the effects. I have Martin Logan mains, but kept my Polk f/x 1000 rears. They sound better than anything else I have heard so far. And unless you are a real movie freak, why pay more for something you will hear maybe 20% of the time? Although I would not go too small or cheap in case you might want to hear music 5.1 formats or have all speakers on at once. Hope that helps-good luck, Michael
I have experimented for the last year with direct radiating and dipole/bipole. For Dolby digital I prefer direct radiating and so have my guests. There is no absolute here,unlike the front three channels I believe you have a lot more latitude with rears. Beg or borrow various designs and experiment;this is very much a subjective decision.
Been in your spot. My processor does music surround very well which sounds a lot better with a direct radiator. Also with Dolby pro-logic II taking hold and offering discrete channels when decoding old dolby prologic rear channels, I think dipolars are going to gradually diappear. I could not make a good recommend surrounds without knowing your front speakers. You want the surrounds to be close in sound to the mains. It does make a big difference. But with that said, I will say the the M&K tri-poles are the best sounding surround speakers that I have heard. They can be switched to operate in direct radition or dipole or three poles at the same time. If your speakers are a match for those then your problem is solved. You can switch back and forth.