Hi Sean,
I would say the sonic benfits of the OB1i over the FB1i are subtle. It's (OB1i) not a speaker that knocks you down and makes you forget everything you've ever heard, it's a very inconspicuous floorstander. The more time spent with OB1i will allow you to get a hold of its character... I would say that the step up from the FB1i would yield a slight but noticeable improvement in separation, less colouration through the midrange, and lower distortion in the lower frequency register. Where the FB1i is the more rocking, troubled youth of a floorstander, the OB1i is the more sophisticated, college educated member of the kayaking team... Does that make sense? I would not personally make the recommendation to move up from one to the other, as I don't think it will offer the satisfaction the I think you are after.
That said, the jump from FB1i to PB1i would be the absolute one to make, and the only one that I would recommend. With the PB1i the power handling, seperation, imaging, bass response, are all vastly improved. One could say it is basically the FB1i combined with the OB1i, the rocking character of the FB1i, and the sophistication of the OB1i. Very nice indeed, worth having a listen if anything.
For surrounds, I've used the Wafers and the DB1i, both are plenty capable of an invigorating performance. Any of our models can be mixed and matched with a Wafer or bookshelf. With blu ray especially, since PMC can handle "!

DYNAMIC

!", the cinematic experience is enthralling.
Hope this helps.
Ian