A lot of my favorite beers fit neatly into several BJCP style categories. Many of the hoppy amber ales from California, for example, may fit better in the "American Pale Ale" category than "American Amber Ale" and many more Pale Ales could be considered IPA's as well. Cross-national style categories are of particular interest to me. If an American brewer produces something which closely resembles a Dusseldorf Altbier, he may well call it an "American Amber" or something like that.
In tasting an IPA that I recently made with only summit hops, I was considering this sliding style scale. I meant for the beer to be an American-hopped ESB, but the efficiency was higher than planned (I got a 15% jump in efficiency when my LHBS got a new mill), so I increased the hopping a bit to put it into English IPA territory. What I am tasting now is so clearly an American Pale Ale to my tastebuds. On paper the IBUs (50) are too high, but the low co-humulone of the summits have led me to consider this a more malt/hop balanced beer than an IPA, particularly given the yeast used (S-04) and the fermentation temperature (72F) lent considerable fruitiness.
So what is an English IPA, really? I don't even know if the style needs to exist. Most beers called IPA in Britain are just bitters with more hops. I never once saw an IPA in Britain that was over 6% abv, that's for sure. Near as I can tell, an English IPA, according to BJCP is just an American pale ale with English hops and malt. Given how many American breweries use English yeast as their house strain, that's how I see it, anyway.
Do other people have the same difficulty I do with determining what to call a beer? Do certain differentiations just seem like they don't need to be there? I feel like IPA should be one category and American Amber Ale doesn't need to exist since Altbier, APA, and ESB tend to encompass the style well enough. And there should be a "Golden Ale" option in lieu of "Blonde Ale" to account for Cream Ales, Blonde Ales, and the British equivalents.
Ok, my 2¢.