I'm a late-comer to the lovefest, but no less enthusiastic. I will say right off the bat that I am in a unique position which has allowed me to see Act I consistently, but I have yet to see Act II. I do however own the soundtrack (which has played nonstop on my iPod since Tuesday) and I have a pretty good sense at this point of how things go down. I'll just touch on a few things that interest me that perhaps haven't been touched on or have only been touched on briefly.
First, there are mixed suggestions here and elsewhere as to how damning the show is of psychiatry and/or psychiatric medication. The show certainly gives a solid ribbing to pharmacology, as Dr. Fine is a humorously flat character who associates mental health with the absence of personal identity. Dr. Madden is certainly more rounded however, at least from what I've seen and gathered. His attempts to help Diane never come off as callous or dismissive; rather, I think he truly believes in the power of what he's learned as a doctor, to a fault. In his overconfident way, he seems unable to fathom how other factors in Diane's life might be affecting her mental state (i.e. Dan's outright denial of Gabe). I know I'm biased as the son of a psychiatrist, but I don't see any of Madden's choices as inherently wrong, simply too shallow for this complex situation.
Second, I find it interesting that people are referring to Gabe as a "ghost," without pretense. I must wonder if this is to suggest that A) the concept of ghosts is being used metaphorically in your wording, B) you really believe in ghosts, or C) you saw N2N as taking a foray into the fantastical and "unrealistic" world. I tend most towards A, and I wouldn't use the term ghost but rather spirit (splitting hairs, I know), simply because no matter what else Gabe is, what's most clear is that he represents the "spirit" of the family's dysfunction. And I like the idea one posed that each family member conceives him differently.
Most importantly, I would like to address an element of the human drama I don't think has been mentioned at all, which is Dan's utter DEPENDENCE on Diane. This struck me most of all about his character, even more than the revelation with Gabe (although the two are intrinsically tied), partly as someone who has also been dating someone since college (no babies). It is scary how deeply I feel Dan's dependence, and it actually causes me to step back and look at myself more closely. This is not to suggest that such early relationships can't be healthy. I would simply highlight the fact that Dan seems willing to do anything to help and keep Diane EXCEPT share her grief, something he might have an easier time of if his world wasn't so centered on his wife. Certainly her absence, however short, long or everlasting, shall help him develop as an individual.
Finally... I know that early on, someone mentioned that we shouldn't focus on Aaron's looks, but man... youthful energy, raw talent, and chiseled features... can anybody say bi-curious?
BEST SHOW EVER!!!