At first I agreed with the posts that BSG didn't need an episode like this but then I changed me mind. Yes we don't know the full reason why Moore needs to tell us about some of the characters back story, some of it makes sense and connects with the main story (Baltar's father and being an overall empty vessel) and some of it doesn't...yet. What this episode was trying to do was make the viewer get to know a side of the characters that we hadn;t seen before so when the story eventually plays out, we feel an emotional loss. Its clear that these characters play a pivotal role in the final episode but Daybreak part 1 was a good episode and as others point out, its part 1 of 3, not a standalone.
How I think things will play out.
The Black hole which is defending the cyclon colony is the same black hole that Starbuck dissappeared into back at the end of season 3, this black hole also connects to Earth. Throughout the series, Starbuck has been referred to by the hybrids (and now her husband) as the Harbinger of Death and will lead Humanity to its doom. Starbuck will lead a portion of the galactica army to the cyclon colony which will eventually lead to both sides destruction. To complete the cycle, some of the characters will survive the 'end' and go through the black hole to earth, the earth of the past, ie 2000 years ago. The survivors will most likely be in a raptor around Orbit and will warn the Earth cyclons of what has occured. These 'Angels' will warn the Final Five of Earths past and set things in motion. One of the 'Angels' will be Baltar, he has done nothing selfless his entire life, this will be his reincarnation, ironically as the one true god he has been pilgrimming since exhile.
All this has happenned before, and will happen again.