Why do people keep mentioning bass? Rock isn't centered on bass, but on mids. Hip hop, funk, a lot of dance music, and much electronica really need strong bass. Rock as a genre does not. Sure there are exceptions, but as long as you get a solid bass guitar and occasional lower drums, you're generally set with rock. On the other hand, the key instruments of rock, vocals and guitars, are mids mids mids.
Of course there's also the issue of punchiness (i.e., impact given by quickness and not by sheer bass) being more valuable than soundstage for rock, which is why it makes Grados shine: they're probably the fastest headphones available at most price points.
For mids if not for punchiness, the K240. For punchiness, the DT531. On the cheap end, I'd go MB Quart 55x (later renamed/updated as the 240) for rock.