My travels to Costa Rica have included many places, except the Pacific Coast....cannot comment on luxury travel as I was lucky enough to have a local American friend drive me all over in his own car. Using San Jose as a starting point, we drove to Fortuna, a very cool town, along the way passing small towns of Zarcero (awesome tropical topiary gardens), San Ramon, San Carlos.
A must see is Tabacon Hot Springs: www.tabacon.com.
Awesome thermal pools and waterfalls. Eye candy scale was a 10/10. I believe they have a resort there, with spa, etc. I never even took advantage of their spa facilities, as the hot springs were amazing. Remeber sliding down a natural slide into some hot springs and having a grand time! Great bar, restaurant, pool.
My friend lives on the Caribbean side, so we quickly drove through Limon (scary and ugly) down to Punta Uva and Puerto Viejo.
I heard from many travelers that Tortugeuro is very nice, lots of eco tourism and nature, wildlife, giant turtle nesting grounds. Would like to see that someday.
Arenal Lake and volcano