I know Shure SRH-1840 is about 100$ more expensive compare to Bowers & Wilkins P7 but which one do u think should I choose? (the difference 100$ does not matter to me). I like headphones with an impact and well controlled bass and good sound stage. The songs I mainly listen to are from: Backstreet boys, Westlife and classical musics. I don't have a headphone amp and I plan to pair it mostly with my Ipod Nano. Please give me the positives and negatives of these 2 headphones particularly the "sound taste" of each .