Running the HD600 with a mint is pretty much the same as running them without an amp - if you're going to get the HD600/650 you'll want a high end amp and good source for them, just like any $400+ headphones really. Running them from anything other than a good CD player/amp setup is a waste of time IMO.
I'm not a big fan of the HD600 from any setup personally, they just aren't my cup of tea - too laid back, rather dull to listen to. Even from high end setups.
If I listened to a lot more classical and jazz I might like them more, but they just aren't right (to my ears) for rock, pop, dance, trance, electronica, hiphop or even acoustic music.
I think a lot of people jump on the HD600/650 bandwagon because they're the most expensive of Sennheisers "affordable" lineup, it's very rare for people who audition the HD650 in store to buy them if they listen to other similarly priced headphones (and even some cheaper models).
Much like most of Sennheisers range, we're more likely to sell them if people DON'T listen to them first and that's saying something.