The Xonar dg is only $30. Probably best bang for the buck. For music, just make sure you have a good set of speakers. And if you're not doing surround, the spdif port on your mobo might be a good option.
But wouldn't using the Spdif mean using the DAC on the receiver?
I would not recommend digital MOBO out sound you want a good DAC for nice sound not Onboard Mobo sound. I beleve you hit the nail on the head with the Xonar DG recommendation because it has a great DAC
if you can just increase your budget abit and go for the asus xonar essense st, since its the best card for music right now, or try to find a used or a refubrished one,
I currently own a recon3d pcie and thinking of buying one my self, but slightly hesitated cuz my primary concern in gaming.