I used to have a rack, servers, all that; it was overkill but learning it was my hobby. But then I learned it, and it became a PITA to babysit all of it. These days I have kids, and my main need is streaming Pixar movies to the living room, music to the kitchen, TV shows to the bedrooms, Rocky to my iPad when I'm on the treadmill... and I wanted something that just works. And for me, that's Apple and iTunes for now.
So its a 27" iMac running iTunes, with a 3TB internal drive to store everything, A cheap WD drive as a backup, another SSD I back up to and take to work with me, and Im looking into a cloud backup. After having a series of expensive drives and RAIDs and Drobos that seemed to go belly up just as often as the cheap drives, I realized that quantity>quality when it comes to backups.
An Airport Extreme with 802.11ac gives me the bandwidth, and two Airport Expresses strategically placed in the bedroom and kitchen can stream music and boost my signal. Security isn't a bit concern for me right now; my work and private data stays on my encrypted laptop, if anyone broke into my iMac they'd only be able to steal a copy of WoW and a bunch of movies and AACs I totally didn't steal in the first place.