First make sure you have a power supply that can handle two of those strong cards. I would just get the one card now; if you can afford sli now, why not just get a 780 btw? Anyhow, if the 770 goes on sale later then you can always get a second one right? You can enjoy most games on maximum settings with the 770 if you are on a single hi def setup already. Unless you are using ultra 4k hd and or multi-monitors then you don't really need sli to run most games at maxed out graphics settings.