I'm probably not adding a lot to this thread, but...
I have a Mini running as a media server, and I just added Indigo to the mix. I honestly couldn't be happier. It's a dual-core 2.3GHz with 8GB RAM, a 500GB HDD, and it's running stock OS X Lion (not the Server version). I am using an external Drobo (4-bay) for my media storage. It's been a great box, has the power I need, and is relatively quiet (unfortunately I can't say the same for the Drobo, but it's not too
loud I guess). It's connected directly to my television also via HDMI; I watch video on Plex, Hulu Desktop and iTunes on a regular basis, and sometimes Safari for web content.
Anyway, yeah, I would highly recommend the Mini for Indigo, and as an all-around home server/media machine.