Here is a chart of US natural gas (source) going back 25 years. Adjusted for inflation, gas has never been cheaper. Compared to oil and coal on an energy equivalent basis, gas is far cheaper than it has ever been.
Here are three big US gas producers, Chesapeake, Encana and Southwestern, all of whom have been beaten down to 2008 levels (chart from yahoo):
Finally, here is a composite sentiment measure (sentimenttrader.com), which suggests that investor sentiment, which is a contrary indicator at extremes, has never been more negative on the sector:
An NG long could even be paired directly against a crude short, since such a large difference between NG and crude or coal simply cannot last in a market economy. Even if gas stays low as economic activity slows, crude will likely come down.