the problem is that hip hop and rock are on opposite ends of the spectrum. Its hard to find a headphone that does both, but imo safe bet would be the 840's. They are the most neutral of the 3 that you picked, so they might not perform as well when it comes to a specific genre, but the overall performance would generally be better.
edit: How bout checkin out the Senn HD25-1 II's, they do both genres fairly well for me. Although not the greatest, (my MTPC does rap better, and 325i's do rock better), they sound fun and are portable at the same time.