Well, to add to my previous impressions, I must say I was actually rather surprised at the popularity of the Audeze LCD2 and 3 models. Sure, they both sound phenomenal, and you'll get no argument from me there, but considering the weight and clamping force of these headphones, I personally would much rather own either the Sennheiser HD800s or the Beyerdynamic Tesla T1s, both of which are extremely comfortable, and don't sacrifice much in the way of sound quality when compared to the LCD2 and 3s (at least, in my opinion).
On the other hand, I was VERY impressed by the Mad Dog headphones by MrSpeakers (modified Fostex T50-RP). For the price ($300), I thought they were a truly phenomenal headphone. When compared back-to-back with the Thunderpants, I found them to be much more even-keel and neutral across the spectrum, while still remaining quite detailed and clear for a closed-back headphone. The Thunderpants headphones, by contrast, struck me as being much more of a basshead headphone, curiously enough, which I wasn't expecting at all. Dan Clark (Mr. Speakers) was also very generous with his time in explaining the measurements he took as far as trying to improve resolution and soundstaging as compared to the stock T50-RP. He is an electrical engineer that has worked in audio for quite some time, and he obviously knows his stuff. The headphones should probably be used with an amp to sound their best, though, even though they have a very low 50ohm impedance rating, and could potentially be driven directly off an i-pod.
Anyway, just thought I'd give him a little plug since I was quite impressed by that particular headset, and I haven't seen them discussed on the forums as of yet.
