What are your top 3 'niche' subreddits in terms of adding actual VALUE to your everyday life?

EDIT: Wow this blew up, thanks everyone for the great suggestions! I will be subscribing my ass off tonight =)

EDIT2: Some people must have a very different definition of value than the one I use =)

EDIT3: I'm going to do some analysis tomorrow and post a histogram of the sub's mentioned in here! Thanks everyone!