What cables should I buy.?

I am building my Music and HT system.
I am in need of help in regards to interconnect and
speakers cables. Which one I should buy?
I am a little confused: people's opinion is controversial
in the amount of money that it should be paid for cables. "Cable just carry the signal".
I have the Proceed pre/pro AVP2+6 channels, the Proceed AMP5
and the Jm Lab Utopia Diva Speakers.
Do I need also power cords for my components?
Thanks