I'm looking for headphones that are as good as my HD600s but with a different sound signature. I'm willing to spend up to $350 and I would prefer portable headphones that dont require an amp. I have a Bottlehead Crack Tube Amp that works perfectly with the HD600s but supposedly is not good for low impedance cans. I've realized that I am somewhat of a basshead, so I'm looking for closed-back headphones that have more energy and bass than the HD600. I'm willing to sacrifice soundstage and accuracy for a more "fun" full sound. I may actually be a treblehead too because I find myself using the treble booster EQ setting when listening to my Ipod. Ive auditioned a few headphones at best buy, which is the only place around for me to do so, and the only one worthy of what I'm looking for (and actually sounded very good) was the Bowers and Wilkins P5. It is my #1 choice right now, #2 being buying another full sized headphone such as the Beyerdynamic DT990 pro (I know they're open headphones) which would be another good match with my Bottlehead amp. I'm also very interested in hearing more about if the V-Moda M80, Sennheiser Amperior/Momentum, Ultrasone HFI 580/680/780, Philips Fidelio L1, or any other portable no-amp-required headphones that would be more suited to what I'm looking for. I mostly listen to hard rock and guitar driven jazz and blues, but also like the occasional electronic/dubstep to hear what kind of amazing sounds my headphones are capable of. Also would like to find a good headphone for watching movies and playing video games. I know its a lot to cover but I'm trying to get in the research and hear some opinions to make a good purchase. Thanks.