DH and I had a, um, healthy social life pre-kids. 
We're now parents to two toddlers and have no baby-sitters on tap. Staying in really is our going out.
On a Friday and a Saturday, we put the kids to bed at 7 and cook a nice meal and will get through up to two bottles of wine on a Friday and Satuay night. Sometimes only one, sometimes one and a half, sometimes two.
This is now our wind-down, grown up, relaxing and having a nice time time. We'd be miserable without it!!
I dunno. When I see threads like this I tend to think that the nay-sayers probably never really did have much of a social life or a misspent youth, even in their youth...
Amongst my circle this is utterly normal. Probably not the absolute best and healthiest option out there, but when I weigh it up against the rest of my life - I eat well, and exercise daily, get loads of fresh air and walk everywhere. I'm 5"9' and a size 10/12, so a very normal BMI range.
I dunno - this is my vice and I'm quite happy with it. :) You only live once and I'd rather enjoy another Pinot pottering around the kitchen talking shite, or scooched into the sofa with my DH than think, 'ooh, that's' enough now, better screw the cap back on, tut, tut'.