I have finally received (or they are in transit) all the components that will be making up my system, as follows:
1. Emotiva XPA-5 amp
2. Onkyo 885 pre/pro
3. Cox Cable Motorola HD cable box dvr w/HDMI
4. Sony PS3
5. Maybe Panasonic BD30 HDMI (might move it to kids room and just use PS3)

As we all know, there are many many possible connections on most components. I just want to be sure that HDMI is all that I should be using for my connections. This stuff is heavy, and once in the cabinet, I don't want to have to move it again if I can help it.

As long as all the components have HDMI connections then HDMI is the preferred way to go.

HDMI all the way.

You obviously need some analog connections between your pre-amp and your amplifier, so of course you're not going HDMI there. So no, HDMI is not all you'll be using. You will likely also need to connect speakers, and of course utilize some power cords to plug stuff in...