In my experience SLI ain't worth it. I had two GTX 680 (actually still do, just not using that PC much). It just introduces own myriad of issues and annoyances, extra stuttering while fps gains aren't really good. Some games refuse to play well with SLI enabled and sometimes performance gets worse compared to one card. Quite frankly for 1080p gaming there ain't much use of it.
As for mobos, regardless of the brand you'll go with just keep in mind those 'high-end'/'gamery' ones often enough aren't really worth the price premium - they don't really offer better performance, just excess of bells and whistles, and feature-heavy ones are more prone to have issues and hardware conflicts than more basic boards, so really I would suggest to choose by the features you'll need. Doesn't mean you should rush for cheapest ones either, those tend to be aimed at OEMs, but even a budget board with Z97 chipset around $100 mark will do fine.
If you like playing Skyrim with tons of mods then perhaps extra VRAM would come handy, so may be that's something to consider.
For SSD brands I'd suggest going with Intel, Samsung, alternatively Crucial does make fine SSDs as far as price/quality goes.
