I would tell my best friend to "Live long and prosper" because we both love Star Trek and I'm always Spock. I'd also probably do the Vulcan salute. Yeah, that's right. Nerd in the house. Not that that's anything new for my fellow Nerdfighterians.
I would say "unquote" haha, but really i don't know what i would say because its kind of an "in the moment" thing, ya Know? Like in this moment here and now, you don't know when or where you're going to die. It all depends on the moment, and who you are. You won't really know until the moment comes along. But, i think it would be really cool to say Unquote :) but it would be cooler if your first words were quote!
I think if you think too much about a fancy-pants last sentence, there's probably a good chance that you will die saying 'oh shit!' as you desperately scramble through your memory (or your pockets, if by some reason you've written it down) in search of those perfect last words. And even if you remember your 'perfect' last words, at the time you are dying, they probably won't be the most apropriate for the circumstances. I say save your creativity for last words for your death bed, and meanwhile focus on the present. Isn't that what the book is all about?