[NOTE: We've moved this discussion from the thread at http://chowhound.chow.com/topics/831386 -- The Chowhound Team]
Yeah, I feel that tacos are one of those things like bagels that some people can get extremely regional with. I didn't grow up in Southern California (although I have eaten from LA taco trucks and recommended hole-in-the walls in Southern California) so I guess it's lost on me, but although my Texas or So Cal friends belabor how bad our tacos are in Boston, even they can't tangibly describe why tacos are just so much better back home.
Obviously regional food is often best in its region (although they may exist, I haven't been to any fantastic New-England style seafood shacks in California) so I do feel like a little slack has to be cut to restaurants making great food who are "attempting" authenticity (whatever that extremely vague term means). I tend to compare these places to other places in Boston, rather than to the "genuine" article.
My question for you hounds who grew up eating tacos is what is the holy grail of tacos? What is the superlative taco? I know price obviously factors in and clearly double tortillas (hopefully house made), but what else makes a taco great? And where should I go in Boston for tacos?