We're not too picky. Outlaw to Outlaw would be a pretty good choice for asking about audio racks. And you're certainly in the right place for 990 questions.

Both HDMI inputs will accept video from DVI sources - the only difference is that one HDMI source offers a stereo analog input for audio in case you want to connect a DVI device to the TV and need to send audio to the TV's internal speakers. Since you have a home theater to take care of the audio, you could connect DVI sources to either input. If your sources don't have DVI or HDMI outputs, however, there's no need to worry about the HDMI inputs on your TV because the 990's DVI switching does not transcode analog video signals (composite, s-video, and component) to digital (DVI).