Of newish artists I would say:
Dan Auerbach-Keep it Hid. Auerbach is the frontman of The Black Keys, this album is significantly slower than most Black Keys stuff. It is phenomenal.
Jose Gonzalez- Veneer. Crazy good guitarist. Argentinian descent, Swedish born and raised. Folky and great.
The XX- The XX ... IMO the best debut album of the past 15 years. (This one isnt really underrated, but if you haven't heard it, to listen to it now)
Atmosphere- God Loves Ugly. Also not sure if its underrated, but It's a great album. And from your selection of albums I assume you will love them, if you aren't already familiar with them.