Adorama offers the Sennheiser HD 650 Over-Ear Headphones in Titanium/Silver for $299. This $25 mail-in-rebate drops it to $274. With free shipping, that's tied with our expired mention from five days ago as the lowest total price we've seen. (It's a low now by $53.) These open-back circumaural headphones feature a 10Hz to 39.5kHz frequency response, 300-ohm impedance, detachable cable, and aluminum voice coils. Rebate expires May 5.