Not sure if this will get any love here because they're pretty inexpensive, but I just picked up a pair of the Audio Technica ATH-AD700 open headphones.. and I'm pretty much floored.
http://www.amazon.com/Technica-ATH-A...4885304&sr=8-1
The best part is, they are only $100. These are widely praised on head-fi, so I took the plunge.
Now, keep in mind, these look
ridiculous. They are huMONgous, and they are gold and purple. If you can get past that, you're rewarded with what is said to be the best soundstage for any headphones up to several times the price.
I previously owned the Beyer DT770, and actually much prefer the AD700s. It's true the raw slam of the bass in the Beyers is missing in the ATs, but there's still more than enough bass for my tastes (for full disclosure I have the bass boost lightly enabled in my soundcard properties). The mid-range and highs absolutely trounce the Beyers imo, partially no doubt due to the ATs' open nature. No contest over all, and my coworker, to whom I sold the Beyers last year, agrees. (Note that at no point did I use a traditional headphone amplifier with the Beyers, just the headphone jack on my receiver.)
Another nicety is the headphones' low resistance: 32 ohms. I plugged them into my iPhone, and while they got plenty loud enough, it was clear they weren't being driven to their potential. I plugged them into the headphone-out on the receiver hooked to my computer and it was night and day. The clarity is outstanding.
Maybe the AKG K-701s are better. The Sennheiser HD650's are almost certainly better. But those cost several times as much and require even more of an investment in the form of an amplifier.
If you are in the market for a nice set of headphones around $200 or less, save yourself a Benjamin and pick these up from Amazon.