I like the unfiltered varieties the best.
Braggs is the most commonly found, but Eden is excellent as well
Here is what it looks like, so you can be on the look out for it
http://bragg.com/products/acv.html
http://www.edenfoods.com/store/product_info.php?products_id=103480
They are basically identical - I like that the eden is in brown glass, but really, its vinegar, if it goes bad, what does it become?!?!? Anyhow, my state has such a bad economy that I try to buy all the Michigan made stuff that I can...so I go with the Eden (practically everything they make is awesome)
Anyhow - any grocer that has a decent selection should have one of those....
Dont go for the clear transparent varieties, if it doesnt get cloudy when you shake it, its most likely not the real deal