Charlie Wright's International Bar. Hoxton.

Just a hop, skip and a jump from Old Street and you're a whole world a way and a few centuries back in time. Ignoring the now-ubiquitous Thai-restaurant-within-a-pub (though I'm assured the food is both good and cheap), you find yourself in an intimate, old world jazz bar. The usual Shoreditch crowd are nowhere to be seen, as jazz lovers relax on comfy sofas to hear the best resident and visiting bands and local jam sessions (Mondays), whilst sipping on reasonably priced drinks. At the weekends its a rowdier, but still unpretentious and music-centric affair and there's almost no hint that the post-modern world ever came into existence.