Only in the beginning. Once you start, you'll barely spend time with Skyrim, and a lot with the CK. Believe me
Tell me about it. A friend of mine does just that, she spends tons of time in there and I ask her, what are you modding? And she's still working on her house
I'm not sure if any of them have NPCs (though my http://www.skyrimrealestate.com/html/challenges.html has Dwemer bots), but there's a range of excellent houses in many different styles.
I love http://skyrim.nexusmods.com/mods/20212 as my starter house. It's got everything you need, except a wood-chopping block and an NPC. Lots of storage, and all very compact. Also, pretty cool design.
I'm not sure if any of them have NPCs (though my http://www.skyrimrealestate.com/html/challenges.html has Dwemer bots), but there's a range of excellent houses in many different styles.
I do believe Brendan62's Autumn Lodge does. He seems to like putting NPC's in his places.
I really don't like any house mod.. There was one that just changed some features in the Windhelm house, but that's the only one I can think of.. Personally I like a house mod that isn't a building from the normal game copy and pasted.. But its tough finding those so I stick with the normal homes..