Welcome
It's been decades since I owned headphones (back in the dorms they were a perfect choice), but from what I know the HE-500 offer world class performance. You really didn't mess around with your first jump into the audio pond did you?
Going the headphone route (versus speakers) makes life much simpler. No worries about the room, technology options are more limited, various domestic factors don't apply, and cost is much less for the same level of detail. But you're tethered, and imaging is compromised.
Comfort is critical for long term use and the HE-500 are big and heavy but well balanced, yet can still be fatiguing to wear. They're over the ear sealed design, so aren't for folks who are very warm blooded or sweat a lot. Even though it's a sealed design it provides minimal isolation from outside sound, which is another personal preference issue. Thankfully after market ear pads are available (look into Focus) for these popular high-end headphones.
The HE-500 use planar magnetic technology which is very inefficient, so they require a somewhat powerful amp. The HE-500 provides a rather polite sound (like classic BBC monitors). Frequency response is even handed and immerses you into the music (not a reproduction of it) but aren't the most dynamic headphone out there. Presentation is smooth, full, natural, organic, textured, detailed, and laid back with great all around bass.
I like the detachable cable feature as the stock cables are rather light weight, microphonic, and kinks easily. Overall build quality is good. Being such a good headphone you'll not want to skimp on quality of amplification or source as they deserve it and will reveal every shortcoming.
I'd start by looking at the Schiit Lyr headphone amp ($449 - very reasonable, high quality/output, American made). Head-fi.org is an excellent place to find amplifier recommendations. The state of digital inputs is a fast moving target, so best to separate it from the amp. To match the quality of the HE-500 you could easily spend $4,000 for source + DAC.
