I like quirky baseball sites, especially if they can teach me things I don't know, or get me to think about things in a way I haven't before. I also enjoy the perspective of some former players (the articulate ones), because they can give you an insight that Bill James or Jayson Stark can't, no matter how brilliant they are, since they've never been on the field with the live ammo flying.
One such site I stumbled across today was http://www.brentmayne.com. The site's content is produced by 15-year major league catcher Brent Mayne. It's heavy on catching, but the blog is good, and I think it can teach you something you don't know.