Bought an external DAC during the week, decided on a Cambridge DacMagic Plus as it was one of the few that has all the features I was looking for and didn't cost upwards of 1k.  Previously I was using an ASUS Xonar HDAV Deluxe sound card which was reputed to have a pretty decent DAC on it already, so I was a bit hesitant going in but all that doubt went out the window after about 5 minutes of listening, daaaaaamn this thing is nice, everything just sounds so much cleaner with a lot more detail, very happy with the purchase.  
Also picked up a pair of Beyer DT770pro's a couple of weeks back as a fun pair of cans for doof doof etc, I love my DT880's but being fairly neutral they can be a bit boring for real high impact music, the 770's are the complete opposite haha they pack so much bass, the high's are a little harsh for metal but I love them for electronica and hiphop etc.
Pic of new setup, PC  ->  DacMagic+  ->  Matrix M-Stage  ->  Beyerdynamics DT880 & DT770pro's.

One of my favorite features which didn't seem to be present on a lot of other DAC's I looked at was that it has a digital out pass through, which I run to my Yamaha receiver for when I'm using my real speakers, which is most of the time.  That meant I was able to ditch the sound card from my PC altogether which neatened it up a wee bit more as the ASUS card required an ugly molex cable that I was unable to hide 

  Could have just used the onboard optical/coax on my motherboard for the digital out but that would mean changing the audio output in windows each time that I swap between cans or speakers, a pretty minor thing but it's way more convenient the way I've got it setup now.