Two good books are "Know Hunting" -Dr. David E. Samuel is the author i believe
and "In Defense of Hunting" by James Swan ,I believe ,is another good one. so instead of one liners just tell them the truth as to why you hunt and if they want to discuss it further you'll have read the books and have a variety of angles from which you can defend hunting if you feel it necessary.

i know several vegetarians and vegan's and they don't bother me about my hunting, for several reasons, but most importantly because they know i'm educated and respectful to them and I don't take for granted where my meat comes from with out any thought to the animal that died for me to eat. they know it's alot more work then the PETA propaganda and lies would have you believe. they are all hypocrites in the end, there is no debate there. i don't mind too many questions because usually the answer is "no, thats not true." then explain why I know both sides of the arguement and they should stop believing everything they read until they hear the other side. See alot of problems come from people who don't participate in hunting, judging the imperfections of it, as if anything in life is perfect and not full of compromise.
there not all bad people, but PETA is all about who can be more extreme, it's just something to fill a hole in there life, they aren't seeking the truth, only to extend there own agenda and feel noble or special. Too many hunters allow themselves to fall into similar thinking patterns in my opinion.