I guess Hollywood Hills Night Clubhouse because of the radio. I actually park my avi there, turn on Hair Bands and do stuff around the house.
First space I bought was Red Bull House of Skate. No regrets since you can't get it anymore.
Well out of the many personal spaces i own, i must say The Playground Apartment is my pick.
As for the Bonus question my first apartment was the Summer House sooo very long ago and i dont regret buying it even though i dont vidit it often but it is decorated. But my second apartment purchased was the Apacolyptic Shelter now that i regret buying lol