What is the difference between Retro, Vintage, and old/tacky?

Now, many words have similiar meanings, but have different connotations. But what I'm talking about is, what makes something old and boring or old and awesome? The vintage era is upon us, and has been for quite some time. "Ugh, that's so seventies!" vs. "This is awesome! Does it fit?"

Two of my brothers are into vintage clothing and shoes and they look dang good! But there must be a fine line between retro and tacky. Some of the old-time-y architecture and furniture is amazing! But some of those fabrics...blegh!

Where is the line? Is it a taste thing?

Where does this:


(Which I see as the epitome of awesome vintage)

Become this:


(Which is just on the line, to me)

Then finally, it becomes this:


And this:


No, just...no.