Hi Crimson,

How big is your room?

If you intend to use hi-rez sources (/HDMI) then HD621 is a pre-requisite for whatever Meridian gear you choose to get.

Spend most of $$ on speakers first-electronics (and its upgrade) can come later.

For electronics - *if* possible, I recommend you getting a 861v4 or better (there are good deals locally). I would skip G series.

DSP6K is a favorite and 5500HC would be a great center to have/match with the speakers.

Regards,
Kishore
P.S. The updated DSP7K is not bad - AFAIK they share same electronics with 6K and 5.5K.