The monitor was in sleep mode and when I woke it I got these vertical lines. I don't know if this was caused by my the GPU or the LCD. I toggled it off/on and it disappeared.
Nope, but when on my mac my 2407WFP will have an odd glitch where some pixels with get stuck blue over some images (obviously where their not supposed to be blue) coming out of sleep. Fixed by, you guessed it, turning the monitor off and on. Being that it does not happen when connected to a PC, I'd say it was the GPU.