My house is located in Yanille, as my main use for it at the moment is as a gateway to everywhere else. I have no real desire to move my house anywhere else, as it is pretty much doing all I want it to do right now.
I've placed my Chapel next to the Exit Portal for quick prayer regeneration and prayer training. The Portal Chamber adjacent to the Chapel has the teleports for the prayer-using tasks I do (Camelot for Dagannoth Kings, Ardougne for Slayer and Kharyll for Barrows). The Quest Hall with stairs up is also next to the Exit Portal for quick access to upstairs.