Fair point, if they work for you cable down! I was going to suggest the monster turbine pro line (gold/copper), but then I remembered the OP wants lightweight (presumably which would resist falling out because of weight), and they are rather heavy for earphones. Perhaps a second-hand pair of JVC FX-700's... But they're a little north of $300 at retail, and their mids are slightly pulled back, so not totally neutral outside of the bass.... Hmmmm, choices.
I'll second the FX700's... south of 300 on the F/S forums, but I wouldn't consider them light... just a bit lighter than the MPTG's, I wouldn't call them neutral... but moreso balanced, because of the low's and high's with the mids taking just a slight backseat, but the mids sure are detailed and lush to make up for it.