Single window

Shift + Space / Ctrl + Up arrow = Maximize single window

Quick assign Subsurf

Ctrl+1 = Subsurf level 1
Ctrl+2 = Subsurf level 2
Ctrl+3 = Subsurf level 3
Ctrl+4 = Subsurf level 4
Ctrl+5 = Subsurf level 5

Ctrl+0 = Subsurf level 0

Make links... (subsurf)

1. Edit Subsurf value of master object.
2. Select target object/s and then select master object.
3. Ctrl+L and modifier.
4. Now all selected objects have same Subsurf value.