There's a few options for cardiff
If you wanna stay in city centre, in and around the stadium, then the top end of st marys street by the castle will be liverpool. There, you have the city arms, the gatekeeper ( a 'spoons with big plasma tvs) and various smaller pubs such as the queens vaults, the cottage etc
The bottom end of st marys by the station will be west ham. that includes things such as o'neills, the philharmonic and the other spoons (cant remember name, its a hole). The quarter brewery, being a mix of resturants and bars, might be both, as might the walkabout further on down st marys.
In the town cente, but away from the stadium you'll find bar haha, slug and lettuce and bar cuba. theyre more upmarket and will only have smaller screens.
Or theres cathays, which is student land. very good pubs, cheap food and booze, and with this weather we've got, many a feamle studend in very little....