The RTi's are generally power hungry, so the suggestions steering you toward separate amplification are pretty good.

Power: Speaker as one ME to another, the biggest benefit of the separate amp isn't so much in the power rating as in the power supply. The 7125's nothing but a big box full of amp channels (similar to the Denon), heat sinks for effective heat rejection (more so than the Denon, because there's more space available for it), and a big toroidal transformer (again, bigger than the power supply transformer in the Denon). The transformer means that there's more power reserve available to take care of those moments when the signal jumps up.

Setup: The 990's pretty user-friendly, even before you factor in the crew at Outlaw and the crowd around here to help out. The auto-setup is a good place to start, but a little time tossed in doing manual tweaking is worthwhile. Aside from the channel calibration stuff, the 990's setup is about as straightforward as you'll find.

Video switching: It sounds like you've got a handle on your needs here. This is probably the one item that could present an argument in favor of the Denon, although there are of course ways to cope with the two DVI inputs.

Other Thoughts: Denon's got a pretty solid reputation, particularly as you move higher up the product line. On the other hand, Outlaw's also got a solid rep - the 990 offers very pleasing sound quality, a healthy array of options, and strong customer support.