What spkr wire and hdmi cable ?

[sumik]

Hello sorry for yet another post. I should've put it in my previous one from few days ago but I forgot. I'm geting Onkyo 606 and Polk RM6750 spkrs and I'm not sure on what cable to get. I tried fathers speaker wire on polks but it was just too thick. I checked http://www.monoprice.com and they have different kind of wire 12awg, 14awg, 16awg and 18awg but i don't know the difference and I don't won't it to b too thick so it won't fit the speaker output.
Also I need short 3ft hdmi to run from ps3 and dvd to receiver, I already have 2 hdmi inwall going to plasma. And yet again, so many diferent kind u can get yet they all look the same.