temple bar street is the most famous street full of pubs in city centre.
can measily go to seaside, there is biggest city park in dublin, phonix park, lots shops in city centre, or you can go to Dundrum shopping centre, which probably the biggest shopping mall in europe.
Several ABer's (myself included) have frequently recommended Gallagher's Boxty House for a great meal at sensible prices: http://www.boxtyhouse.ie/
In most cities I'd advise avoiding the open-top tours. However, Dublin's attractions are well spread out and using the hop-on, hop-off services makes a lot of sense. (You also get discounts on certain attractions).
The Guinness Storehouse is very popular. There are some great views of the city from the top, which you can enjoy while savouring the 'free' pint which is included in price of admission: http://www.guinness-storehouse.com/
Travel south into tipperary , great people fantastic scenery and more interesting than dublin , which afteralll is a major city , and has all the crime etc associated with it.
Dublin is the only place ive been that had bouncers 0n all the takeawayu shops .macdonalds burgerking supermacs all have 24 hour security on doors ,and that was 8 years ago and is still the same today