Theater Sound Xperience may not be perfect for all scenarios, but it is able to easily provide a surprisingly decent upgrade path for consumers. Just don't expect it to outperform modern headsets as advanced features are lacking.
NuForce uDAC-2 packs great sound quality and convenience into one small package. Even compared to premium sound cards like the Xonar D2X, the uDAC-2 can stand out in a class of its own and it is definitely worth $129.
With clean sound reproduction, DSP processors that add new dimensions to the music, and surround sound that makes any pair of headphones into a capable home theater system, the Xonar U1 USB is an excellent product.