For the LOD, make sure you get the cryo frozen silver cables and 24k gold plated connectors.
For a Dap, the Clip+ will be fine, costs about $30 I think, actually the regular Clip is fine too, about $20.
You'll need a high end portable amplifier, be prepared to spend around $300.
Sennhesier HD600/650 is fine for a first headphone, just make sure (again) you upgrade the cables, it's much more practical than IEM's, and great for quality Flac listening on the go."
Sorry, I was in a sarcastic mood.
Here is my real (opposite) advice.
- Don't worry about cables upgrades, at all.
- The Clip+ is overrated, it's very small and cheap and sound good for it's size, but that's it, there are better DAPs.
- Don't worry about portable amplifiers, unless you really want to take something like the HD600 around with you.
- Senn HD600/650 are good but not for portable use, especially since they're open-air. There are lots of cheaper and more practical alternatives, like IEM's.
The E11 is probably sufficient for the HD600/650, but the E11 is a portable amplifier and if you're only going to have the HD600/650 desk-bound then you should invest in a desktop amp instead since they're better than portable amps.