Some more thoughts:

Some of the new receivers with 6.1 or 7.1 capability are quite large. Make
sure you have room in any cabinet you want to put them in and that there is
good ventillation otherwise you run the risk of the amps shutting down due
to overheating. Also realize that you will need quite a bit of room behind
the receiver to deal with the large number of cables you'll be connecting.

Also, unless you plan to purchase a sophisticated remote, make sure you can
live with the one that comes with the receiver. There is an surprising
variability in the quality of the ergonomics in this often overlooked
component. When you get your selection of components narrowed down, then
search the internet for user reviews which will often mention such small but
ultimately significant details.