I heard once on Oxford SciBar (I think that one - http://www.oxfordscibar.com/september-2011.html) a scientist who said that universe could really come from nothing, if all energy in it summed up to 0.
EDIT
BTW. Oxford SciBar is an awesome event, so if one lives or happens to stay in Oxford for some time, it's worth checking out.
EDIT
BTW. Oxford SciBar is an awesome event, so if one lives or happens to stay in Oxford for some time, it's worth checking out.