depends. every once and a while my boyfriend used to shave/trim his chest. he was also in really good shape and his hair wasn't very thick at all in the first place. I think for people with at least a little muscle definition, shaving it actually looks pretty good if he wants to remove the hair (although I'm not any more or less attracted to hair or no hair). If you're in mediocre or shape but have a jungle growing on your chest, by all means remove or trim it, but if you just have a little here and there I say leave it alone
Also I don't think guys should mess with their arm hair
I've been with a guy who had chest hair and it was never an issue. I don't think I find it "hot" when a guys chest is shaved. It is what it is... as long as it's not to the point where it covers your chest completely. Try trimming it and see how you like it so you can have a perspective of trimmed vs. full grown.