=====CT – Foxon Park soda! – the birch beer is my favorite. I guess birch beer could be considred a regional New England drink.===

I’ll second the nomination for Foxon Park. It’s the official birch beer of all the well known appizza places in New Haven. This company has other great flavors too.
I think that efuery is also correct about this flavor’s popularity since no national brand makes it.
Hot Dog Johnny’s in Buttzville, NJ. has a reddish version of the drink and I have found a something similar to that here in CT. It doesn’t have to be clear, but it is unique.

mark