Had a fantastic week in Dubrovnik (stayed inside walled old town) and another fantastic week on an island further north (Mljet).
Don't swim off Dubrovnik unless you like swimming in cigarette butts and floating bags though..
When a cruise ship comes in, it overshadows the town, and the place fills up for the day, but the evenings are splendid.
Walk up the hill outside town (Srd hill... there's a cable car too, but I preferred to walk) to the museum at the top... fascinating.
As ever, people love it if you can 'do' a bit of the language

or at least have a go.