I wrote the player myself. I used the Bass library, which was easy enough to learn. I also found the Arduino fairly easy to code for. I'm usually one to complain about inadequate documentation, but still found both of these things relatively easy to just get done what I want without needing to hunt through too many sources for direction.
The NFC interface is one of three I'm using. It's purpose is, unsurprisingly, for starting an album when I'm not at my PC, or for a guest to easily play an album. When I'm already at the PC, though, I have a browser-based interface and a more command-like interface.
Thanks again to Scott. Sounds like I'll go for two discrete devices. I toyed with the idea of using NFC for the control functions as well (instead of buttons - something like a cube whose faces activate different functions when held to the NFC reader), but that seems more like using NFC just because you can, not because it's the best option.