I own both the Sony HT-CT150 and the Yamaha YSP2200 - both entirely different beasts, with the former being a sound bar and the latter being a sound projector. Like you, I did tons of research before finally deciding on a winner. I found the Yamaha at a price I couldn't resist and paired it with my Kuro 101fd. After that, I was began to research budget sound bars to pair with my 70 inch Sharp Aquos.
It really comes down to the sound bar that has features you value the most. You mention that, first and foremost, you want the best surround experience. For that, I would say the Sony HT-CT150 is the clear winner from the other candidates. The HTCT-150 is also the only 3.1 offering from your list, with the rest being 2.1 systems. However, it does not have bluetooth connectivity. I'm not sure how much you value Bluetooth connectivity, but, for me, HDMI connectivity is much more valuable than Bluetooth connectivity. Although the HT-CT150 does not decode Dolby HD and DTS HD, your bluray player can perform the decoding and the HDMI cable has enough bandwidth to carry the decoded audio LPCM (optical cable CANNOT do this).
I am very familiar with the Sony systems so I will break them down for you:
I would avoid the HT-CT260 like the plague. It looks horrible and has no HDMI connectivity. I'm not sure how it performs since it's fairly new, but the lack of HDMI connections is a big minus in my book.
I listened to the HT-CT550 at Best Buy (not the ideal place to judge a sound bar) and it sounded OK. However, I hate how the receiver is a separate unit, meaning you have three components - the bar, the sub and the receiver. It's ability to decode HD formats means nothing to me, since almost all current bluray players (including your PS3) can do the decoding before sending the signal to the sound system. Most of the reviews I've read are mixed, and a lot of AVS members prefer the HT-CT150 over it.
I am extremely pleased with my HT-CT150, especially with the current $183 price at Amazon. From the reviews that I've read, the HT-CT150 and the HT-CT350 are the best out of the budget sound bars at creating a surround experience. The HT-CT350 is superior to the HT-CT150, as it has a better quality sound bar which has 6 total drivers as opposed to 3 on the HT-CT150. Sadly, it has been discontinued, though you may be able to snatch one up from eBay or Craigslist. The surround experience from my HT-CT150 is noticeable, though I do not hear anything behind me (I don't hear anything behind me with my YSP2200 either). When using the sound setup that's included on most Pixar films (the one that plays sound from each individual channel), I can clearly hear the sounds from the center, left and right channels where they are supposed to be. The surround left and right are in the middle of the room as opposed to the back.
To sum it up, if you want the best surround experience at a budget price with ample connectivity options, the HT-CT150 is the clear winner. If you can find a used HT-CT350 then I would jump on that, since the sound bar has a total of 6 drivers as opposed to 3 on the HT-CT150. None of these have Bluetooth connectivity, but I would place a premium on sound quality over Bluetooth connectivity.
Have you considered the Samsung HW-E551? It has pretty good reviews and has two HDMI inputs and is Bluetooth capable. You can also configure it as a sound bar or as two separate speakers, which should help with the separation of the left and right channels and create a more enveloping experience.