Dublin's food scene has improved enormously since the lean years. The city now has a serious restaurant culture concentrated around the city centre and the neighbourhoods south of the Grand Canal. The market worth knowing is Howth for fresh seafood, and the city-centre pubs mostly serve reliable, unfussy food at lunch.
The Irish breakfast — bacon, eggs, sausages, black and white pudding, grilled tomato, toast — is the best meal of the day and widely available. For lunch, the pubs around Merrion Square and Baggot Street are good options. For dinner, Grafton Street, Dame Street, and the streets around Temple Bar have the highest concentration of restaurants, with everything from simple bistros to more ambitious Irish cooking using local produce.
Sunday lunch remains an important ritual. Book ahead if you're eating out on a Sunday.