Dear SG
I lived in Belfast for 15 years and moved to Dublin two years ago. The social scene is really good and I would recommend the following:
Malmaison: Near city centre and trendy Cathedral quarter about £140 per nite but really special, nice food and lounge.
Ten Square : Behind City Hall and has good Grill bistro and bar, plus upstairs fancy restaurant. Not sure of prices but mid-range I guess.
Guest House: Ravenhill Guesthouse on Ravenhill Road, one mile from City Centre and about £60 per nite. Victorian and lovely.
Restaurants: one or two new Japanese - zen in Adelaide St nr City Hall and Waterfront (not sure of name mabye Teppanyaki?) in front of Waterfront Hall and Hilton Hotel.
Paul Rankin's cayenne in Shaftesbury Square, great atmos and serves til 11. Great local food, lots of choice, top quality.
Deanes downtown = 3* Michelin stars, pricey but v special or also Deanes Deli round the corner from BBC on Bedford Street.
Bars: the Merchant hotel cocktail bar downtown is lovely. It's v expensive to stay here but beautiful place you should at least visit.
Nicks Warehouse - oldest city centre restaurant, wins awards for value, is in Bridgestone Guide and serves great Irish food. Pork chops are huge!
I would recommend you get a copy of the Bridgestone Guide to Northern Ireland - has all the best places, reviews, phone numbers and addresses.
Hope you have a great time.
Best regards