The nothing-est nothing we have any reason to think you'd ever get to (or rather come from? lul,) is the kind Lawrence Krauss talks about.
http://www.youtube.com/watch?v=7ImvlS8PLIo
Mike Riovanes
I can believe we were once a single celled organism and we've branched from some genetic pool. How that Genetic pool came to be, I don't know. I mean hell, I came from a Sperm Cell on a hot night between my mom and dad. No Mystical Entity was apart of my growth, birth etc.
I see likenesses with animals and humans all the time, it only makes sense we came from something similiar in my eyes.
Evolution is a different subject than cosmological origins. But anyway the origin of genes isn't all that rough to work out in vague chemical terms. For a long time we thought organic molecules were the big stopping block but the Miller Urey experiment dismissed that notion (and subsequent experiments did a much better job of explaining the origin of organic molecules.)
Then you're stuck with how they came together to form a cell. Darwin pictured a warm little pool full of them just kind of coming together- a lot of the "large" parts of a cell would work here but it isn't such a good explanation for things like setting up RNA and proteins for metabolism. The hydrothermal vents in the deep ocean set up these harsh chemical gradients where you could get some of that working before having a cell proper, and the tree of life seems to point in that direction as well.
*Third option people bring up for "how did we get here" is that the first cell on Earth was an alien- that life came from some other planet. Might be the case but then you just move the root of the tree of life back and still have to answer how the roots began.
But anyway origin of organic molecules and then origin of metabolism are the two spots you'd want to look into.