Need help choosing a Card

I decided to make the jump from console gaming to pc gaming. I was almost about to over spend on an alienware aurora until I got introduced to building my own. Granted I am a complete noob when it comes to computers however after spending hours researching I know pretty much what parts I am going to buy, plus I have a friend who will help put it together. Now here comes the biggest headache of them all..... Choosing a graphics card. My budge it $600.00 and I know I want a NVIDIA card. My problem is which one. Right now I will only be using one monitor (1080p), however would eventually within a years time have 2. Types of games I will be playing is BF3 Arma2 (eventually Battlefield 4 and arma 3), fallout and skyrim type games. mostly FPS and RPGs. I keep going back and forth with the 670 and 680 and all I know is that I want the 4gb versions. Right now I am not interested in overclocking mostly due to my inexperience with PCs, plus I heard it voids the warranty. I want to be able to get at least 2 years of playing the games and their eventual sequels mentioned above on high-ultra setting without any issues at all. I will be using i5 3570k processor with a ASUS sabertooth z77 motherboard. What card without having to overclocking myself would you recommend and why. I figure by end of 2014/beginning of 2015 I will upgrade my card. Should I go sli or is that over kill for one monitor. Please help

Oh and before you say 670 or 680 please state which kind and why. There are different brands (EVGA, MSI, ASUS, etc.). And different types (classified, FTW, SC, et).