There's nothing wrong with being an Intel fan. Honestly, Intel is better for more expensive builds (+$1500-$2000) but for a low cost build that's skill high quality and preforms well, AMD is the way to go (in my opinion).
So, next you cannot SLI two different GPUs. (that is in the situation that you are using SLI to refer to using Nvidia cards) But you can Crossfire two different model cards aslong as they are both AMD. (For those of you who don't now CrossFireX is the AMD version of Nvidia's SLI) But on the other hand you can SLI two different BRANDS of Nvidia cards. Say you have a 2GB EVGA 660 and a 2GB MSI 660, that would work. (also includes Asus, Gigabyte, etc.)
(BTW most AMD CPUs ARE better for he price)
A FX-8350($195) easily beats and Intel i5-3570k ($220) in performance.