It's been brought up a few times but I gotta reiterate how perfect Yamaha's EPH-100 is for a basshead. It's got kick, solid musical separation and clear mids and distinct but not piercing highs. A buddy recommended these after I asked for an IEM version of the V-Moda M100 and I've been in love with them ever since trying them on. They satisfy my bass love while not compromising other areas of the audio spectrum.
I just play them out of my iphone, unamped and I couldn't be happier. Such a fun and high quality sounding pair of IEMs. I was coming from the Klipsch Image S4 and now am damn near disgusted with their sound in comparison to the Yamahas.
There is an issue with fakes, so be sure to buy from an authorized dealer. If buying from amazon, make sure it's listed as actually being sold by Amazon.com and not a third party. Audioaffair in the UK is where I got mine, and for a few bucks cheaper even with overseas shipping:
http://www.audioaffair.co.uk/yamaha-eph100-earphones/