Digital BW, The Print

The choice of a 1.8 or 2.2 gamma in your monitor calibration is
independent of the working spaces you define in Photoshop. For LCD
monitor calibration you generally want to use a gamma that is close to
the native gamma of the display itself. This reduces the hit to the 8
bit video card data during calibration. LCDs have a native gamma
closer to 2.2 than 1.8, so 2.2 is what is often recommended. Whichever
gamma you choose when calinrating your monitor, Photoshop will make
the necessary adjustments to whatever working space you choose.
-- 
amadou diallo
Author, Mastering Digital Black and White
www.masteringdigitalbwbook.com