Have you checked the footage on an HD monitor set up to color bars? Or, you could set up your computer monitor to bars.

Easy fix
 

Okay alot of answers on this, but the solution is simple dude. Set up your camera through the firewire and open Final cut pro. Set camera on video mode instead of VCR mode so you can see what the camera sees on you final cut window. Make sure you have the preset on the camera you will use. Now, on the camera, adjust the lcd image settings in the camera menu until the lcd image matches the window live preview in finalcut. Also I would do this adjustment in low light to get the worst case scenario fixed.
Easy. This is what I did and so when i shoot a wedding, what I see in my LCD is exactly what i will see on my monitor when I edit.

That solution is not exactly simple and definitely not ideal. As I mentioned before, FCP corrects the gamma so if you calibrated the camera LCD to FCP, the exported video would turn out washed out. And you shouldn't be rely on the brightness of the LCD to guage exposure anyway.