Well I'm gonna be not much help on the receiver. Just taking a quick glance at it I noticed that it has no phono inputs; no S-video, or component inputs (important if you want to run your video through your receiver); only 2 digital inputs (1 coax, 1 optical - not really enough); and is really only 70W per channel. Repeating that I really don't know that much about this model, I'd rather see you with the
1804 ($299). But, If others more knowledgeable disagree, I'd listen to them.
This should help you understand 5.1/6.1/7.1/DTS/DD, etc.
Yes, Dolby PLI is obsolete, And, I hate to break it to you, but Dolby PLIIx has been released now, so PLII is fading into the sunset also. (I don't think "obsolete" is the proper word. It's just that there are now newer technologies available.)