To be honest Sennheiser headphones are having a blast with the X5, mine just can't take its plug out of the X5, it wants to marry it.
The HD800 for me will definitively be my next purchase, that is when I'll be able to deal with the price. Transporting the dap without an amp is a huge plus, that is one quality it has that is hard to beat.
X7 is the dap I had in mind when I notice the FiiO posts, I can confidently say it will be spectacular and talked about when released, the specs are going to be too great to pass and now with the magic from the engineering team at FiiO and let's not forget a price point that will be very attractive, you'll feel the need to add it to your listening arsenal.