I love the aesthetic of Riven, though I liked the original Myst, when I saw this running on my Mac in 1997 I was blown away by the Cinematic quality, and spent many a while just engrossed in the detail of the locations. Not suprisingly the production designer was an ex ILM concept designer - Richard Vander Wende
Riven's World was definetly an inspiration to me, a visual look that I was attuned to my informative years growing up in the Dales of England, with its old ruined castles, rivers and impenetrable woods, as well as an Engineering Father that took us to see Steam Trains, Beam Engines and other Steampunky Victorian MachinerY.
For the last year, I've been doing bits and pieces for a non-profit sim in Second Life called - Story Island - for Media that Matters. The design of the island's architecture and landscaping has been definetly had the Myst games as a big influence.