I would save the money and SLI later on, when you need the extra performance.
As for SSD, I would go with something a bit more "new" than the Crucial M4. Don't get me wrong, it's a good, reliable drive. Heck, you probably wouldn't see much of a performance difference anyways. But I'd go with a Samsung 840 Pro, Plextor M5P, or Kingston HyperX 3K.
Just my input. In the end, it's up to you. Research, research, research
@Lukethebeast12 If you live near a Microcenter, you can get a huge discount via in-store pickup on the i5 3570k and select motherboards.
Also, you can get pretty much the same performance out of a GTX 670 as the GTX 680. There's really no reason to spend $150+ on the GTX 680. That money can be put towards a larger capacity SSD. Try this...