Have you run into any issues with it? Plays 1080p x264 videos smoothly? Anything to be aware of/limitations?
rasbmc can be flakey, at least the version I tried. If you are running a 256MB board, don't even bother with it, it will lock up on you while trying to navigate menus and playback video at the same time (which is what it is designed to do, you can't avoid this); you really need a 512MB (rev2) board to make it work. Occasionally, I'll get video stutter on some high bitrate files (really high 5+mbit burst) when streaming from samba/nfs but I'm not sure if this is a network problem or a raspi problem (raspi seems to be capped at around 80mbps effective bw). It has hardware assisted decoding for mpeg4 and h264, so as long as you're not trying to stream your DVD images (mpeg2), it's pretty durn quick and seamless, even at 1080p24&p30 (I don't have any p60s, or I'd try it). Decoding is based on ffmpeg as far as I can tell, so it's very compatible and accurate demuxing & decoding. I use stereo out because I'm sending to a monitor (hdmi->dvi converter) instead of to a TV so I can't speak on the hdmi audio output, but I'm sure proper futzing with pulseaudio will get it working. The plugins for TV show metadata in xbmc suck, even with configured "properly" and have a hard time recognizing folders & subfolders, but it plays back the files just fine from the browser.
tl;dr version, if you're already running XBMC and like how it handles, pick up a raspi model B rev2. A fully kitted out rpi w/ case, psu, and storage will probably run you 70-80$ and if it isn't suitable for your media playback needs, you can always repurpose it as a seriously overpowered garage door opener.