@jayrammusic: no appliance is going to come close to the performance of your custom built pc. stick with it 
You’ve already done it for the most part, but focus on getting your audio away from the electrical storm that is happening in that PC. RoonBridge (formerly known as RoonSpeakers) and RoonReady endpoints should get you there.
As for open headphones, @brian and I love the Sennheiser HD600/HD650 – I also own the HD800, but the HD600 is the set I love. Get a good amp for them – it’ll be better than most speakers out there