Seriously spazzer, there's no such thing as fav aperture size to shoot with. It all depends on what's in front of you, and what picture do you have in your mind before you pressed the shutter. You adjust the camera's settings (aperture,shutter speed = exposure) to try your best to achieve what you have in your mind.
Therefore, we cannot give you the correct answer becos there is no correct answer.
We can't read your mind or see your vision.
Only you can......
ps: if you're not sure how does changing the aperture or shutter speed affect your pictures, i suggest you google the terms and learn abt it. With the knowledge, you can then apply them to the situations you're in)
Cheers!