Help Me Decide

[Fishman2010]

Hello,
I have been reading the threads and reviews for two days, some of them are based off completely different setups. So I thought it would be ok to make a new thread.

My setup is:

Small area, but open space (high ceilings, etc.)
Samsung 42" 720p Plasma
Panasonic BD655K
DVR Cable Box
Xbox 360

I'm looking at getting the Onkyo HT-3300.

My questions are:

1. Does it have a receiver or repeater (whatever the difference is), and does it matter?
2. Does it decode HD audio formats that are found on Blu-rays?
3. Any other useful info I should know?

Would I be better off getting the Onkyo HT-5300?

I like that it has a powered sub, 2 extra speakers, and they are a little bit higher powered. The only thing that concerns me is there are 4 one star reviews and they seem to be for the same reason, the back channels are reversed with multichannel PCM (or something like that). Also they said the audio will drop out in certain cases. Any info on this?

I'm sorry for the "noob" questions, I will be the first to admit I pretty much know nothing about audio. I know quite a bit about displays, but when it comes to audio I know about as much as a new born baby .

I just want to make sure I get the most out of my games and Blu-ray, I can SEE Blu-ray..... now I want to HEAR it .

Anything I buy can't be worse than what I'm using now, Bose Companion 3 computer speakers [*crickets chirp*]. Yes, I know......

Thanks