While the words "audiophile" and "budget" are usually mutually exclusive, this is an area we're keen to explore here at CNET, especially in the Audiophiliac blog. Products like the Pioneer SP-BS22-LR bookshelf speakers and the Lepai LP-2020A+ demonstrate that good hi-fi can be had for a little more than pocket change.
As far as the enthusiast community is concerned, the Superlux HD681 headphones belong in this list, and there are several sites dedicated to these incredibly cheap headphones. There is even a page detailing how to mod them (PDF) to squeeze even more performance out of your roughly $30 investment.
There are several versions of these headphones available overseas, the HD681F and HD681B with slightly different frequency responses and designs, but only the HD681 model is available in the U.S.
Design
The headphones are surprisingly well-built for the small amount of money paid, with a sturdy plastic frame and vinyl earcups that encircle your ears comfortably. The only issue is that these headphones can only be described as "terrifyingly ugly." They look like a sewing machine accident. Too many red knobs and strange mechanical gears. These are the steampunk soundtrack to an afternoon of stitching together a sweater.

Further reinforcing the "Dear God, stay at home!" aesthetic is the long 8-foot cable, which should snake across most living rooms to your stereo.
While you probably won't need it, the headphones also include a vinyl bag for transporting them -- presumably from room to room.
But what are these headphones for? The faint lettering on the bottom gives a clue: "Professional Monitor." These are for critical listening applications and so have a forward presentation that is designed to pick out details or flaws in music. However, note that the headphones are semi-open and so may cause sound leakage issues in a home monitoring/recording situation.
Discuss Superlux HD681 headphones