Photoshop Colour Settings

[NigelC]

In setting up the colour settings in CS2, the prompts suggest using Gray Gamma 1.8 for a Mac monitor and 2.2 for Windows. I have a Windows laptop attached to an Apple Cinema Display so which should I use? and does it make a difference?Also my version of CS2 doesn't have Europe Prepress 2 in the Settings, but when you change the working spaces the Settings box defaults to Custom anyway.