If you don´t want to move too far away I´d say the coast of Croatia has a lot of potential to become a big(ger) backpacker destination.
Can´t say anything about Ireland - never been there except a brief visit to Dublin. I wonder why it´s so popular though. It´s not exactly near anything, it rains 11 months a year and it´s ridiculously expensive.
Maybe Boston would be Irish enough for you? Everybody says it´s a great city, but it has not yet any really decent hostels.
Seriously, though: how much money do you have? Like everything in life, finding a location is not only determined by your preference, but probably more by what you can afford.