Ambience:
eitehr Olav's or Roxey Inn. Somethign about the mix of folks that show up there. LIstening to them all ramble on always makes me

Convenience:
I really like Drunken Dragon Inn. It's right in a zone where one can collect tons of ingredients, combine them, and sell the potions to the Innkeeper there. Forget his name.
Favorite negligent innkeeper:
That lady who runs the Tiber Septim Hotel. She charges 40 gold but totally neglects to charge for that HUGE feast of food upstairs!