I travel to Japan once a year, and because gift-giving is part of the culture there, for hosts, teachers etc. I bring stuff over.
In the past I've tended to lean towards independent whiskey and poitin (Teeling, Cooley when it was Irish-owned etc.) but since they've started selling O'Hara's three packs at Dublin airport I've gone that route once or twice as well.
If I really had my pick I would probably choose something that is not just a good beer but is appealingly packaged as well. O'Hara's hits the former mark, but it's labelling is a bit 'blah' in my opinion.
Dungarvan could be a good shout. But if you're talking about hauling things around to give to bartenders then perhaps 330ml bottles would be a better bet ... 8 Degrees, Porterhouse etc?