One thing that doesn't often get mentioned is that a Pi is a pretty decent way to play around with Risc Os. Probably better than digging up some old Archimedes/RiscPC or the overpriced replacement machines.
If you're going to use the raspberry pi to do file sharing type things, i highly recommend checking out bittorrent sync.<p>it allows you to turn the pi into your own cloud server.
I just finished setting up my raspberry pi as a personal router / firewall, to redirect my internet traffic over a VPN to a server i set up in europe. I'm building a chrome extension, and matching node.js app to allow to me toggle the routing on the raspberry pi from within my browser.<p>I got sick of fighting my isp's throttling rules, which kicked in at the most frustrating and inopportune times, like halfway through downloading linux ISO's to play with on my raspberry pi.
About audio:<p>The built in line out jacks have just horrible quality. (And I'm someone who doesn't believe in gold cables so for 'audiophiles' it must be torture.) Rather get a USB sound card and hook it up to your pi.<p>Also try out MPD (Music Player Daemon) if you want a juke box. MPD clients are widely available for any platform - you can sit on the couch and control your pi's MPD with a client running on your phone.
Things I use my Raspberry Pi for:<p>* Controlling my TV/AC/other infrared devices around the house: <a href="http://www.stavros.io/posts/how-turn-your-raspberry-pi-infrared-remote-control/" rel="nofollow">http://www.stavros.io/posts/how-turn-your-raspberry-pi-infra...</a><p>* Controlling my garage door/RF sockets/other RF stuff around the house (pretty good range on this, too): <a href="http://www.stavros.io/posts/how-remote-control-rf-devices-raspberry-pi/" rel="nofollow">http://www.stavros.io/posts/how-remote-control-rf-devices-ra...</a><p>* Writing an Android app to make HTTP calls to the Go server that launches the LIRC process, really low latency: <a href="http://www.stavros.io/posts/how-turn-your-raspberry-pi-infrared-remote-control/" rel="nofollow">http://www.stavros.io/posts/how-turn-your-raspberry-pi-infra...</a>
I was using my pi as an airplay receiver for my hi-fi. I'm not sure if they fixed it yet but the analog out was pretty bad (8kHz mono at the tome) but I know the audio quality could be better. So I stopped that then played Minecraft, now I use it to SSH into my house and WOL my ESXi servers, get the ipmi data from the servers and some simple Node stuff.<p>This is the Pi B v1 (256MB) I'm thinking about getting a v2 now.
Nice list. With regards to your choice of music player, I know you said you just wanted something easy to set up, but you might be better off with <i>mpd</i> as you can use a whole bunch of different front ends to it; from web front ends and native binary GUIs, through to command line clients. There's even smartphone apps, so you can use your phone or tablet as a remote control to your hifi.
I am using my Raspberry Pi to record temperatures and humidity in my apartment. After recording I generate nice charts using the HighCharts library: <a href="http://thule.mine.nu/html" rel="nofollow">http://thule.mine.nu/html</a><p>How I did it: <a href="http://thule.mine.nu/html/about.html" rel="nofollow">http://thule.mine.nu/html/about.html</a>