I've spent a lot of time in Dublin over the last few years, both for business and pleasure and love the city and people. My mum is from Ireland and I've seen a lot of changes since my first visit around 1972.
Hotels wise I would reccomend The Merrion if you want the very best in the city, The Raddison Blue if you want modern and safe from a brand and probably The Fitzwilliam for the great location smack on the corner of St Stephens Green and the main shopping area, as well as having the tram right outside the front door for going up or down the coast.
Dining wise I would suggest:
http://www.pichetrestaurant.ie/ (Contemporary cuisine, sensible money for good quality)
http://www.dax.ie/restaurant/ (Voted best in Ireland 2014 in some awards)
http://www.thegreenhouserestaurant.ie/ (Modern, Mich Star type stuff)
http://mulberrygarden.ie (Bit out of town, but great recommendations on this one)
http://pearl-brasserie.com/restaurant/ (Not eaten here, but told its good)
If you stay at or near the Fitzwilliam then Thorntons is worth a look in the hotel, think i carries 1 star. There are many other great places to eat in the city to be fair, its a great place to dine out.