Drive up through the western fjörds, absolutely breathaking!

If you can stay long enough(and if they're open), give the Djupavík Hotel a night or two.*

http://www.djupavik.com/

The southern coast can be beautiful, even if they weathers inclimate. Vík is a great little town, and make sure to hit Jökulsárlón(Iceberg lagoon). Walk around it, take a few hours to explore. Cross the bridge from the main drag where all the tour buses collect, and enjoy the tide moving the big ice chunks around .

Have a fun trip!

-Dan