Normal is however you define yourself, others, and your life on a regular basis. "To be normal, is to be weird. So in a sense if you're weird, you're normal." -me
Sure, some men erect just by seeing a hot girl, some men need to see them naked, but if you're looking at a naked woman and not erect then you may have a problem.
98.6F orally is the classic answer. Temperature varies throughout the day, lower in the morning and higher in the late afternoon. Temperatures over 100.4F are considered fevers.