Receiver for B&W 684 theatre

[Muscleduck]

Hi BR.com

I'm currently building my home theatre. I have gotten to the forst step of buying a proper TV and was thinking about buying a proper surround system.
I found the Bowers & Wilkins 684 theatre. It's a 5.1 system with front, rear, center and sub in 1 package. I found it on hifix.co.uk for 1640 GBP. However, I can't seem to find a good receiver. The main problem is that it appears that most receivers are way to powerful for this set.
The receiver I set my eyes on atm is the Onkyo TX-SR577. It's got 100W @ 8 Ohms. Does anyone have expirience with this receiver or other Onkyo receivers (pref in combination with B&W)?
My brother has B&W 6 series speakers with a Rotel amp to listen to his music. I realy like the combination Rotel/B&W. It has real crisp clean sound.
The problem there is that Rotel is alot more expensive than Onkyo. it Rotel worth the extra buck? I'm thinking of the Rotel RSX-1550. Actualy, the Rotel is a bit too expensive, but if you guys think this receiver realy is worth it's money, maybe I can persuade myself into buying it
Also, what features do I have to watch out for? Things that are a must, or things that I should avoid? I read something about HDMI passthrough being bad but can't remember why.. it had something to do with the audio, DTS-HD MA I believe.
If anyone has remarks on the speakers, or has useful info about these receivers or other receivers, please, let me know
Btw, 4 HDMI inputs should be enough I think. Digital TV, PS3, HDPC for now. 1 output should suffice too.

Thanks

PS: how good/bad is Yamaha. I tend to think of Yamaha as a manufacturer that makes a lot of everything, and thus can never be as good as a manufacturer that makes only receivers and other HiFi oriented products (God I hope this makes sense )

EDIT: sorry, 1 more question: with all this expensive equipment, I want good protection from lightning strikes/power surges/... I saw something called a power conditioner on the internet (in someone's sig here actualy). Is it recommended to have one? If so? What's a good one? I live in Europe btw, so it has to be 220-230V.