Headphones are a big problem, I find I cant "hear" pitch accurately even when I’m using like Sony MDR-7509. The vocals sound great in the headphones but suck through the monitors. I figure there are two possible solutions to this problem:

1) Plug one monitor in "out of phase" with the other and put the mic dead center between them. The monitors phase cancel each other out in the vocal track whilst you can hear everything perfectly whilst singing. I haven’t tried this however I got the idea from a recording magazine !

2) Using the mute switch on the headphone preamp I can kill one side of the headphones and hold the active side to my ear. This allows me to "hear" myself out side the headphone mix whilst keeping the monitor sound out of the mic. This seems to work !