What should I upgrade?


I am in a generally noisy environment, so I tend to stick to headphones, I'm currently setup with my ASUS Xonar Essence STX PCIe Card (TI Burr-Brown PCM1792A DAC 24/192 W/Stock Op-Amps), a pair of Sennheiser HD280 Pro headphones (I think might be the weak part here, they're old as well)

My non headphone setup is the ASUS Xonar card, a pair of Polk TSi 100 Bookshelf speakers, Yamaha RX-V365 Reciever for analog amplification, also of note is that I have primary audio reflection points insulated with foam.

I'm on a budget but willing to save, what component would I need to upgrade, or add, to get the most bang for my hard earned buck? My target audio file is 24/192 FLAC/WAV when I can find them.
zunaro
IMO you should upgrade the Yamaha. Keep the item as a tuner, of course, and purchase a better amp. Investing in the system upstream will not yield the right results IMO, as the Yamaha will probably mask much of any improvement...
Yamaha to me among your components are not the weakest link. I would start with speakers.
For the assumed targetting budget, I'd look for nice vintage speakers such as McIntosh, Tannoy or Spendor within $2...300. There are may b plenty in your local craigslist adds. You can visit sellers personally with your receiver and test them in synergy at recommended listening position. Necessary upkeeping of vintage speakers shouldn't be expensive, but would advise to research first once you find ones you like.

Good luck.
If your primary mode of listening is headphones, I would upgrade them AND get a stand along headphone amp. Give us a budget and we can be more specific w recommendations.