You can't go wrong with a Woo amp just make sure the specs match up well.    I have a $2,500 amp designed for HD800s that sound like crap with my HE-6s. Purchased another amp that power the HE-6s wonderfully and not the HD800s.    I've heard the Woo WA5 and it sounded wonderful. 

I have D5000s for sale. I started out with SRH840s, and to be honest, anything you move up to is better than those.    There are a number of ways you can go based on price point, including Denon AH-D2000, Sennheiser HD-650, etc.    That said, D5000s are amazing for the money if you...

It's interesting when you look at their product guide that the D2Ks share the same drivers as the D5Ks and the D5Ks have the same speaker wire as the D7Ks. 

Eh, I might take that back. I sold someone a Total Bithead who felt that it made his sound better. I would not use gain on them though. 

None of that is necessary. It might actually be detrimental given how bright they sound already. 

Hmmm.... that is a tough call. I would wait to hear the HD700s before making a choice. Personally, I would roll with the HE-6s (used) or HE-500. They're by far superior to most cans in their price range right now. 

Because headphone amps are able to provide constant power at those levels without having any significant spikes. Receivers aren't that sensitive and if there was a spike you could blow you headphones. 

Go for Audio-Technica L3000 if you can find them. If that's too $$$, I'd suggest trying out the Victor JVC DX-1000s. They have the best bass signature of any sub $1,500 can I've heard, but they are slightly bulky; not heavy, just bulky.    My friend wants to sell his, so PM me if interested...

HE-6 HD800 K1K DX1000 LCD2 D5000 D7000 HD650 RS2  

For mainstream stuff -- look for more closed-type headphones, like Denon AH-D2000, AH-D5000, Beyerdynamic DT880, etc. Sennheisers like HD650s have better clarity but aren't as 'fun'. 

Any of the Denon line -- AH-D2000, AH-D5000 or Audio-Technica ATH-M50. 

I would give it more time... the level of bass is something you become adjusted to the more cans you hear. If you listened to some $1,500 HD800s you might feel like they sound like crap, but really they represent bass very accurately. 

HiFiMan HE-500 or HE-6 (if you can find it used). Possible you might be able to find HD-800s used as well for that price. 

For portability, iBassos are good, but a little pricey.    Can't beat the Total Bithead or Total Airhead. TBH also is a USB DAC. 

Yes, I agree with the last person. The HE-500s are awesome but require quite a bit of power.