So in the OP I didn't answer my own question, because it's honestly so hard for me to choose. But after some thought I recalled my fave spot!
Zora's Domain is it for me, hands down - but I actually have a specfic area there that I could end up staying at for long periods of time. Near the top...
This is inspired by a Shoutbox convo last night. Twilight Princess was the first 3D Zelda game that really felt like it had varying geographic locations set in Hyrule. There are quite a bit of cool locations in the game, and I'm wondering which is your favorite? Imagine you were in Link's shoes...