Re. the Guinness Storehouse (not the factory or brewery - you can't visit either) - it's hard to recommend somewhere wholeheartedly that costs €14 to get in, even if that does include a 'free' pint, though you can reduce the entry fee by booking online - http://www.guinness-storehouse.com .

The Old Jameson Distillery - http://www.jamesonwhiskey.com - is better value at €9.75, including a nip (or more than one, if you get involved in the tasting trial) and handy for The Cobblestone and Hughes's.