I was recommended the Audio Technica ATH-D40fs headphones by a local pro shop here in Nashville, who remarked a lot of bass session guys use them. They make a similar ATH-D40 set, but the 40fs version has a 'hump' in the bass response. I wanted something good for headphone practice, and these suit me. Around $90USD.
Be sure and check the ohm-rating. I love the K240's, but at 600ohm resistance, they weren't very loud for some of my gear. I now use a little Mackie mixer with a 1-watt headphone send, so no problem !
J o e y