The Eternal Universe?

I started thinking about the birth of the Universe today. Anyone who would actually read this probably already knows about the standard Big Bang explanation - but I will repeat it anyways.

Einstein's theory of relativity, and numerous observations of distant galaxies, have shown that the universe itself is expanding. A common misconception is that there was an explosion inside of the Universe and that space remains fixed while the stars and galaxies fly apart. The reality is that space itself is expanding (one way to understand this is to draw some stars on a balloon and then inflate it. The stars are not moving relative to the balloon, and yet the distance between them is increasing).
Of course if something is always expanding, it must have started out very small. And in fact the predictions of the Big Bang model have been accurately measured to be accurate - as far back as a fraction of a second after the Big Bang. But there is one problem - at the moment of the Big Bang none of the existing theories of physics are valid. And that means we cannot say what happened before the Big Bang.
In fact, the generally accepted theory is that time started with the Big Bang, so we cannot even probably discuss 'before' the Big Bang. Many people are uncomfortable with time having a beginning - if something happened then something else must have caused it right?

The first option is that the Universe might stop expanding at some point and start contracting again. It would continue to get smaller (and hotter - start the 'End Cosmic Warming' protest!) until it crunched into either a single point or a very tiny miniverse (the Big Crunch). And then that tiny Universe would explode out again in a new Big Bang and create new stars and galaxies. In this model the Universe can continue expanding and contracting eternally with no start or end of time.
The model has an important problem though. Each reborn Universe must be more disorganized than the previous one. So if the Universe has been doing this eternally in the past, stars and galaxies should not even be forming - there is just too much entropy!

But there is another option! We could be one Universe in a giant Multiverse, in which Universes are constantly being created and destroyed. The Multiverse could exist forever without introducing problems.

Yet another option is that there are two Universes that collide occasionally (the Ekpyrotic Universe). Each time they collide they create a Big Bang in each Universe, then they separate and each evolves for billions of years on its own. During the evolution the Universe expands so much that the 'disorder' it contains gets dilluted until it is almost non-existent. Then the Universes collide again and the process repeats. Just like the Multiverse, this process can continue forever with no problems!

So perhaps the Universe is older than we think...