Yet another circumsion thread ugggggg, but anyway...
Why do you want to lop off your foreskin? To look like "everyone else" ? tight foreskin that is hard to retract? Religious reason?
Seems to fully retract :) The foreskin covers the head of the penis protecting it and making it more sensitive when it's uncovered. Without this protection, the glans becomes dry, calloused, and desensitized from exposure and chafing. If you are circumcised there is a greater possibility that you'll have to have more quick and harder thrusts having sex to get the same feeling.
Smell, etc... they make a nifty thing called SOAP and WATER. It seems to work amazingly well when used on a daily basis.
I read that some evolutionary scientists think that the combination of the head of the penis and the foreskin provide a suction action to well draw out any sperm from the vagina left by someone else. ... you have a dickhead and skin so when you're fucking a gal your dick will help to pull out any sperm from a dude who fucked her an hour before you did... imagine if we were bonobo chimpanzees... that might be useful to have a suction device if you wanted to father a kid, and know it was yours :-D
Purpose of the Foreskin
Specialized Nerve Receptors in the Foreskin
Purpose of the appendix
Purpose of appendix believed found - CNN.com