Advice Please - Where to Spend $3-400

With tax refund season approaching :) Its time to consider an upgrade. As a university student I wish my refund was larger ;) But them's the breaks.

My system is:
Quad 21L + NAD C350 + Pioneer DV353
- Monster Interlink mkII 400 between Pioneer & Amp
- Black Rhodium AST 200 BiWire

My thinking is that my money should go towards a source upgrade - either a CD player or a DAC. My budget would be $300-400 USD
Any recommendations either way? I think my Pioneer should prove a decent transport for the time being.

If you think I should grab a new source some recomendations for used CD Players would be nice.

If a DAC my shortlist is
- California Audio Alpha/Delta
- Scott Nixon Tubdac/+
- Channel Islands Audio VDA
- MSB Link DAC

I have an eclectic music taste: Jazz, Electronica, Rock, R&B, and everything in between.

All suggestions are welcome :)

Thanks for your time!

Nathan