Haha, way too many recommendations for a noob like me! So far I've heard O2/ODAC combo, Audinst, Crack, Nuforce, Magni/Modi stack, and even more in other threads. From what I can understand, I need both a decent amp as well as a decent DAC, right?
Would the Magni/Modi stack be a good place to start? It seems like the O2/ODAC isn't appropriate for the HD600s?
Magni/Modi is perfect for all the Sennheisers I own. I actually prefer the Modi over the ODAC that I just sold.
I haven't heard the O2 yet though.
The Magni/Modi will also be good with most every headphone you'll buy later.