Somehow I just love the theory of the Heat Death of the Universe. I much prefer it to the Big Crunch or other possibilities.
It's so dark, so Nordic, existentially bleak and abysmal, that it can't help have but have a certain romantic appeal about it, like listening to early The Cure records, or reading a Kafka book or an essay by Sartre on phenomenological meaningless.
The idea that everything will just slow down, cool down and eventually pop out of existence at random is somehow paradoxically comforting (like Sartre's analogy of fireflies locked in a dark box flickering out); due to its overwhelming inevitability, in that nothing lasts forever, that eventually the Cosmos itself will rest in the peace and oblivion of the absence of existence....anyway I'm getting carried away...who knows, maybe when the Universe loses its very memories and track of time and space itself, conditions will be just right after all for another Big Bang to happen. So there's always a glimmer of hope left (I just heard Roger Penrose talking about this idea and it sounds really interesting).