I really enjoyed both Hidden Expedition: Amazon (one of my favorite HOGs) and Hidden Expedition: Everest.
Now, Big Fish has another hidden expedition game in the pipeline - Hidden Expedition: Devil's Triangle!
They've released screenshots of the game. They look beautiful. Go and see them for yourself!
If this upcoming game is as good as some of the newer Big Fish Studios releases (such as Mystery Case Files: Return to Ravenhearst and Drawn: The Painted Tower), then you should keep $6.99 handy for when this game shows up on the Big Fish site.