I am definitely an Otaku , I watch too much anime and read too much manga to be called anything but an Otaku.
My only short coming my opinion is that I only have one piece of memorabilia and that's my FMA Pocket watch , which I got from England.
Problem is that over here memorabilia is very difficult to come by , in my years of being an Otaku I have only ever found one item and that was an Ichigo hollow mask (1st version) and nothing since then has popped up , the only other way to get that sort of thing here is to order it online but I don't have a credit card.
I don't think people who only watch the popular/well known anime have the right to call themselves anime enthusiasts never mind calling themselves Otakus.