I have a pair of CS3.6's, with an SCS3 center and some older AR surrounds. While my amplification is not up to your level (I have two Adcom GFA-555II's in bridged mono pumping 850w into each of the 3.6's, and an Adcom GFA-2535 feeding the center (bridged) and surrounds), I am very happy with the results that I am getting out of my Rotel RSP-1066. The store that I bought it from (Progressive Audio, in Columbus, Ohio) said that the Krell Showcase was their highest recommendation, but that if you didn't want to (or weren't able to) pay its asking price, the Rotel RSP-1066 was nearly as good for a far lower price. I would love to have all Krell in the preamp/amp department one day, but in the meantime, the Rotel/Adcom setup works well.
How do you like your Merlins with the Thiels? My AR's are nice sounding speakers, but their voicing is a good bit different than the Thiels. So far, in surround use, I haven't really noticed, but I would like to pick up an SACD player within the next year, and my guess is that the different voicings will become more apparent when I do.
Tom.