Are you sure this is correct? If your lens is 18mm, on a camera like the 350D the effective FOV with 1.5x crop factor would be around 27mm, therefore the minimum shutter speed is 1/27 right?
Ahoy there! @ Newbie, welcome to the forums. Here are some good websites to learn about the various parameters:
http://www.kamerasimulator.se/eng/?page_id=2
http://www.photonhead.com/simcam/
doesnt matter. hand held speeds are just generally 1/60-1/100. u wont wanna risk with a 1/30 and below... just personal preference. cause remember, while u minimize handheld speed, ur getting subject blur