The reason I decided to dive in and spend some cash is because I'm an aspiring mixing engineer, and will be primarily mixing on headphones for a while (until I have afford the right room treatment and right monitors). It's direly important for me to hear every nuance of the music, thus I feel as though it's justified. I've never even heard of this website or even headphone amps/DAC's until I decided I needed to get some good headphones for mixing! Normally, I probably would have never dropped this amount of money on headphones, or anything else to listen to music, regardless of how much of a music lover I am.
If your budget is limited, put your money into an interface that has a reasonable headphone output and a modded Fostex T50rp. Save your money for the monitors etc. If you'll be on headphones for a while, a couple different ones wouldn't hurt (but again that chips into the budget) and speaker/room emulation plugins will be your friend.