For protraits - i like to shoot at bigger apertures but not wide open. I like to isolate my subjects in portrait shots most of the time. Usually f2 or f2.8 cos i know i do not have the skills yet to control my DOF that well. If shot at wide open, DOF is very shallow and OOF may occurs if i did not handled properly.
For general landscape - i usually shoot from f5.6-f11 depending on scenarios and condition.
For street shoots - i will usually shoot from f2.8 - f4. I dun want too much isolation here.