I have a set of Sennheiser HD439s that I purchased a number of months ago. It was the first time that I had ever spent a significant amount of money on a set of headphones. They were pretty good, as you would expect. The first time I put them on it was clear that I was listening to a higher class of device, far exceeding cans or earbuds that I have purchased in the past.
These headphones blow them out of the water.
The ATH-M50s stick to your head, holding in every note and making sure that you don't miss a thing. If bass is important, it's here, and these cans can handle anything you throw at them. Black metal, drone, hip-hop, breakcore, classical, psychedelic, everything sounds good here.
There's a reason why these headphones are recommended by every major audiophile site on the internet. Do yourself a favour and give them a try.