Just like to know for normal PS3 & Xbox360, what is the best option for surround sound system currently? I'm on a budget but hope to get the best out of my bucks. I don't have a DAC so i'd need a full system that includes a DAC as DAC are expensive alone. My questions are as below:

1.Is 7.1 better or 5.1 is sufficient?

2.Is it better to get those computer surround sound system like Logitech/Altec Lancing/Creative or a home theater box system like Sony/LG etc?

3.I don't require the speakers to output very loud volumes as in "Rock the house", just decent loudness but good quality sound.

4.If USB compatible would be a plus.

I went to computer shops and did a quick look not many real surround sound system available, the one i saw was a Logitech 5.1 with DAC but it's still cost around 1.2k. I would like to know if there's better options.