The ‘Irish pub’ underneath the shopping centre that’s underneath the office building with the big revolving Mercedes badge on the roof is ‘interesting’, especially if go like German country & western bands playing soft rock power ballads!
Personally I don’t see the point of going to an Irish bar if you are visiting a German city. Kreuzberg would be a good area to head to for a night out. Loads of bars and restaurants to get a real feel of the Berlin flair (it was where Clinton always headed to on his nights off while in Berlin). Failing that Oranienburger Straße is a long road with lots of bars and restaurants (used to be the red light street but has been gentrified now). There is one bar that is an arts collective come squat that is really interesting called Studio 54 if you are into that sort of thing.
There is so much to do in Berlin – it all depends on what you are after… If you are starting by Zoo then I guess Kreuzberg or Schoneberg area are you best bet for restaurants etc – Zoo itself is a bit sleazy in parts and it is harder to find non-touristy spots in Mitte. But if you want culture then head to Mitte.