Yung x2 means dual core, x3 tri-core, etc. Wag mo kunin yung Phenom na luma, mejo outdated na yung architecture. Yung Phenom II, nakakasabay sa Intel processors.
Yung RAM, go for 4gb. You probably won't need anymore than that. Brand doesn't matter much for it. Yung LAN card and modem, built in na sa motherboard yun. The videocard, I'd suggest an ATI HD4830 or the Nvidia equivalent, whichever is cheaper, di ko sure kung magkano yun ngayon, pero magandang bang for the buck yung value nun.
Also, add a decent power supply to your list. Sayang naman yung pc kung puputok dahil sa faulty power supply. Yung akin HEC na 550 watts.