This is such a personal question, you'll never get one answer, and you'll probably end up more confused than you were in the first place. At least I was. Instead of focusing on "the best," focus on finding out what you like. Dynamic drivers are good for this, and they're much more forgiving with amps and other equipment that you'll likely end up adding to the list of things to look into.
This could totally be an unpopular opinion, but I'd say go for the HD58X. They're easy to drive, you can use them most places (I never found sound leak that bad), and they have a reliable sound signature for you to compare to. Forget the amps, or DACs, find out if you want to get punched in the ear drum or if you like more neutral stuff. If you don't like them, the resale market is pretty decent, and they're good backups.
After that, then start exploring based on what you like to hear and what you like to do.