What cpu should I get?

Hi. I'm making my first computer and am not sure what cpu would be best for me. At the moment I'm not much of a gamer at all (the occasional 100 turns of civ 5 before my laptop overheats) but I am a huge multitasker. My average computer session is big bang theory playing in the background while loling at facebook and destroying level 90 on bloons tower defence 5. This usually lasts about 2 minutes before a spectacular overheat! I was looking at the i5-2500k but the idea of having an 8 core fx-8320 deciding the fate of my super monkey is tempting. However, I've heard nothing but terrible things about the AMD and have lived with a terrible terrible AMD laptop for the last 2 years. I'm currently leaning towards the i5 but as this message clearly shows I'm a massive n00b and don't actually know why other than AMD is supposedly lame. Thanks