Sholazar Basin is probably my favorite zone in the entire game. A bit of background, Un'Goro Crater was my previous favorite.
The storyline was really fun, and I loved how your introduction to this place was so cinematic (Flying in, crashing, talking to a guy hanging from a tree,etc.) and how everything progressed from group to group was just awesome. I really enjoyed how you start off helping I think Nessingwary, and somehow go between Wolvar and Gorlocs, and end up with a pretty epic questline helping Freya's Avatar.
The thing that topped it off to me though, was after getting to know this new place and having a few hints from the Avatar talking about a 'similar place' you got to portal back to Un'Goro in a special hidden away location and retrieve the weapon. Just so cool!