Maybe this helps - until December I was a post-doc at ETH Zürich, here is what my last Pay slip has:

Montly Gross - 6500Fr

SUVA (accident insurance) - 0.7466% = 48.55Fr
AHV (Old Age) - 5.05% = 328.25Fr
ALV (unemployment) - 1% = 65Fr
ETH Pension = 307.15Fr

Net - 5751.05Fr

Witholding Tax - 8.09% = 525.85

Take home - 5225.20Fr

Have to pay ~200Fr/mt for health insurance as others mentioned on top of that...

Andrew