I suggest the 650 and O2. :) It would really be all you need. And as a dac, hmm I was very intrigued by the aune t1 myself and I'd like one too. But i'm probably going to wait with it for a while because it's going to cost me a lot of money. I'd probably buy over 20 different tubes. :P I'm still looking for a dac myself. I'm probably going to diy one to save costs.
And when I say that the X1 is a little bit closed sounding it isn't NEARLY as closed as a real closed headphone but it's just slightly closed. I don't even know what closed sounding exactly means so it's just a feeling I have. Nothing concrete. ;)
And Poleepkwa, what system are you talking about?