This may sound weird, but my ACD is way too bright, it's hurting my eyes. Yes, it's the lowest setting. Anyway to get around this? It's the same when hooked up to the MBP or to the PPC Mini. 
What ICC profile do you have it set at?
Did you run through the Color Sync process?
Download this. It "reduces" the brightness of the display by playing with the way OS X renders it's output. I use it nightly because I too find desktop LCD's too bright.
Download this. It "reduces" the brightness of the display by playing with the way OS X renders it's output. I use it nightly because I too find desktop LCD's too bright.