I "discovered" BSG in the local video store one day. "Man" I thought "this is probablly really cheesy. Ah, what the hell". Rented the miniseries then went through the entire first season. I can't think of a time I've been this surprised (pleasantly) by a tv show.
To me, BSG is the only and most effective "processing" of 911 in popular culture. I like Speilberg's War of the Worlds but the 911 imagery felt forced and ham fisted. Have not seen the Greengrass movie and have no desire to. And I've seen the video of the planes going into the WTC once. BSG "re-imagines" and references that event in a way that I can take without being offended or rolling my eyes.
I"m surprised by some on this thread who were put off by the various "visions" various characters have. The explanation does not need to be supernatural: the BSG crew and Cylons could be being manipulated by aliens, highly evolved Humans or Cylons, etc. I do feel the Head Six kind of appears and vanishes with no logic.
What I most like about the series is how the characters have evolved over the seasons. These characters are on a journey, and I think the writers have put a huge burden on themselves to live up to their build up.
Watching BSG has also made me more aware that a series likes this really needs everyone involved to be putting out theie best. As one point of comparison, I used to love Babylon 5, but repeated viewing have made the poor acting, SFX, and wildly inconsistent writing stadn out more and more, to the point where I no longer enjoy watching it. BSG has some weak episodes, but the actors (almost all the actors) sell their characters so well, the production design is almost always spot on, the SFX are great etc. Definetly stands up to repeat viewings.