Hmm last I checked it was just energy density/quantum fluctuations (also known as "nothing, but nothing isn't nothing anymore in physics") <-EVENT HORIZON--------PARTICLE HORIZON-> inflationary period through scalar fields (much like the Higgs field) for N>=60 e-folds -> inflation ends when equation parameters (phi) oscillates around energy density (V(phi)) (or "potential") quantum fluctuations inside of "patches" of scalar fields freeze in, (these are the problems (observations) this theory attempts to fix--->)the result is a vastly inflated universe that is mostly uniform and flat in geometry due to the curvature term being negligible -> reheating // creating entropy from energy density dumping into other fields and particles --> universe evolves into a radiation dominated friedmann-walker-robertson metric universe (a.k.a. standard model) so on and so forth.
Net energy then = 0; Net energy now = 0
The only problem I have with that is that inflation is a mathematical construct that IS solid, but it's untestable. Then again, I wouldn't expect being able to test this kind of equation - so I guess we're stuck with "what theory can predict everything?" And right now inflation does it well. It's also flexible, so parameters can be changed to fit observation and experiment.
Edit:Some reading-
Notes on inflation
http://www.astronomy.ohio-state.edu/~dh ... notes7.pdfOn the zero-energy universe
http://arxiv.org/PS_cache/gr-qc/pdf/0605/0605063v3.pdfThe return of a static universe and the end of cosmology
http://www.springerlink.com/content/c6r ... lltext.pdfThat's basically what I said, but I said it in english (albeit probably with some liberties to make it make sense).