Try tube rolling first.

Using a headphone jack on decent hardware is not sacrilege to me. The Melos SHA-1 was as much a pre-amp as a headphone amp and highly prized. I personally used my McIntosh preamp for years and it was great. Yeah people can get into the details, but quality hardware is quality hardware.

The best way to find out for yourself is to trial a pair.  The 600s are very close to the 580s - they were essentially the same set of cans back in the day, although modern 600s might have materially different drivers now.  If you're going to try something different from the 580s, I'd go for the...

Velvet.  It corresponds to the OEM style.

I tried to insert a link to one of the versions I bought recently but I don't have enough permissions to do that yet.  Just google, ""2 Version Replacement Cushion Ear Pad For HD545 HD565 HD600 HD650 Headphovne"  including the typo.  These are comfortable with good fit.  They include replacement...

Here's a set I purchased: http://www.ebay.com/itm/251893542993?_trksid=p2057872.m2749.l2649&var=550779586683&ssPageName=STRK%3AMEBIDX%3AIT   This includes the foam protectors for the drivers.  Very comfortable with material options.  At first they felt different because they were thicker than...

Most parts are user replaceable. The most expensive are the drivers, but I've had a pair of hd580s for nearly 20 years. I've replaced the foams twice, upgraded the cable and added 650 grills. All took seconds (the cable) to a couple of minutes (the ear foams). Drivers still going strong.

EBay has all sorts of foam aftermarket replacement parts. A lot cheaper. I've used them and they are fine.

I'm very late to this, so you've by now made a decision, but little dot amps have gain settings to accommodate different headphone impedances.  So tube amps can drive low impedance headphones, but not as loud as some comparably spec'd solid state amps.   There's a personal taste question...

I've owned a pair of 580's since the 1990s.  I had considered the 600s, but from what I had read at the time, there was a qualitative difference (small), but mostly it was how they looked.  Years ago a picked up a pair of the metal grilles from Senheisser for $6 each and replaced the plastic. ...