Can never get used to how many Americans have to get passports before the big trip! In most parts of the developed world people have 'em already....

If you're going through central Dublin from the airport, you might try Hughes bar behind the Four Courts for that first pint (tel 01 872 6540). They've got sessions most nights - probably the best in Dublin, these days, and the genuine article, which is more than you could say for the music in the Temple Bar pubs. (Though if you're going to Johnny Fox's, maybe you like things a bit touristy.)

As for the sightseeing in Dublin, if you had only half a day to spare, you could do worse than give the whole half day to a conducted tour of Kilmainham gaol. (The tour doesn't take half a day, but you need to allow for getting there and back - it's a little way out from the centre.)

I'm slightly curious about how long your wife has allowed to "check out London." My stints of living there add up to 13 years and I've barely scratched the surface.