The 4 and 8 ohm rating are the same on the NAD. I believe it is also the same on the Rotel I was looking at. The difference is in the dynamic rating. That will shoot up for the 4ohm. I noticed with arv units they seem to be the same, although a fair amount of them are not rated for 4ohm.
To the original poster, you will be VERY happy with the 60's for music! I just got mine a couple of weeks ago, and last week bought an NAD amp. TONS of power! And I do like it loud. With those speakers and a nice amp, you will not need a sub, until you go multi-channel, IMHO.
By the way, my room is about 14ft x 26ft x 8ft.
Shane D
