Brightness advice for cinema display and Lightroom?

[james*b]

Hi -
Here is a quick question for Aperture/Lightroom/Photoshop users: how do you decide what brightness setting it is best to use for your monitor when editing photos?
I have a c. 2008 20" Apple Cinema Display (A1081).
Thanks in advance,

 

[maflynn]

I have my ACD set so that its bright enough to look washed out in the daytime. Sorry I have no scientific method, but it works for me. I set mine until its visually pleasing. My images in Aperture (I was using LR) seem to be decent when viewed on other computers so I don't think I'm screwing up too badly