Bike Forums - Looking for a new bike

I live in Brooklyn and need to replace my antique cruiser whose seat post has come unattached from the bottom of the frame. sad.

I had already been starting to look for something new - lighter, easy to convert to single speed and eventually fixed gear - but it's intimidating and overwhelming and I'm still pretty lost after days of research.

I'm pretty settled on a 70s or 80s Raleigh, Fuji, or Azuki frame but I want to make sure I get a model of good quality. Is there any way to determine this just by looking? It seems that every time I see an ad I look on here and find out the model is crap quality metal and/or too heavy. Most times the model isn't even indicated so I can't even look into it.

This is kinda making me crazy.