Would my refractory time improve as a result of my instant healing? 'Cause I can think of some nifty ways to spend eternity. 
So I couldn’t starve myself to death, right? Could I go forever without eating? How much weight would I lose and stay alive? For that matter, could I eat a wedding cake every day and not gain a pound?
Don’t you read? Every superman has his kryptonite. Dracula had his stake and silver bullet.
Al Capone had his tax records. Nobody is immortal.
Not to pile on, but Willis kicked no one’s ass in that (ill-conceived) movie.
SPOILER AHEAD:
From what I recall, Willis’ fight with that big psycho at the end of the movie saw him barely escape with his head intact. Yes, he won, but it was no cakewalk. We can assume maybe a 10 to 15 percent strength advantage over a really big guy who was far more ferocious. Uber-bench pressing ability doesn’t neatly translate into fighting prowess, unless you’re Batman, of course.
There was a Highlander episode where the antagonist was someone whom MacLeod had abandoned on a deserted island. He was stuck there for many, many years, constantly dying of dehydration, then coming back to life, then dying, then returning.
He wasn’t too happy with Duncan. Seems that’s not a particularly nice way to die.
Another curious question: Suppose, while doing your superhero thing, you get arrested for murder. And convicted. And escape is impossible.
How would you deal with death by lethal injection? What if you got off “easy” with a life sentence?
Bust my ass, earn a few billion, retire and read, play video games.
What the hell, that’s my life plan now. 
I don’t know why this thread has mutated from a “what to do if immortal” poll to a “how to be a super-hero” poll. I mean, is there enough crime in the real world to justify any metahuman less powerful than Superman dedicating himself to vigilantism?
I’d start a religion.
I can get to things like studying those mystical oriental arts that allow people to distance themselves from pain (to the point of being able to burn to death without flinching) later. But for now, lets start a religion that promises real corporeal immortality for all your worldly wealth and absolute dedication.
First, I would use my talents to ensure that the Pittsburgh Steelers never win another Super Bowl. Mwahahaha!
Which sport?
Okay, seriously, I don’t know. I’m not good at planning ahead and stuff, so I’d probably be living paycheck to paycheck for all eternity. I’d have to learn how to create new identities & whatnot, since I’d have to explain my non-ageing somehow. Luckily, I’ve a look that would probably give me some leeway, but at some point I’d have to adjust my birthday back to an appropriate level.
Personally, I don’t buy the whole tubes-up-my-ass-in-a-secret-government-lab-schtick. Keeping some level of anonyminity, whether I can spell it or not, would be a bigger concern. Frankly, they wouldn’t need me locked up in a lab to study me, the idea that antagonizing me in that way would be beneficial is just silly. I’d visit a research hospital occassionally, I’d be called Patient X, and I’d be the subject of occassional ongoing research studies.
Since I don’t really miss people, I’d probably be good for the job. Going on indefinitely wouldn’t really be that big of an issue for me. I’d want to get admitted to a good school and just study everything; I’d have time for it. I’d want to take frequent vacations to see the world. I might engage in risky jobs — maybe do a stint cleaning up Chernobyl, since I can’t be harmed by the radiation. A year of that would probably pay pretty well, since they could probably use a man on the inside! I’d start a journal, a living history project, and I could probably scratch up some grant money to create a library or something like that. I’d have to spend more time reading & taking in culture so that, hundreds of years from now, I could be a first-hand source for historical research, and people would come from all over to interview me and get my insights on the past. And because I knew what was coming, I could do a much better job preparing to be a primary resource than the typical old person has done. Journals, photos, videos, voice recordings, &c. would all be important aspects of my life to ensure I can communicate the past to the future.
Damn. Now that I think about it, I’d really like that job! Where do I sign?
Can you imagine being immortal and being a Chicago Cubs fan? You still might never get to see them win a World Series! On the other hand, in the year 2516, you can impress everyone with the fact that you were alive the last time the Red Sox won the Series, 502 years ago!
How does immortality let you do that? I guess you could become a pro-ball player yourself, but there are twelve or 15 or so other teams in the league, are there not?
You’d also be pretty much the template of a perfect soldier. Your only guarantee of safety would be total secrecy.
Ever read the Flat Earth books by Tanith Lee? Not normally something I’d recommend, but this thread reminded me of a scenario in one where an immortal pisses off someone who lured him to, and then tossed him into, a pit of lava from which he was unable to escape.
True immortality scares the heck out of me. What do you do in 4.5 billion years when the sun goes? What do you do in 9 billion years, floating in the void, or sitting in your space craft that you built in your free time just to escape the expanding sun. Use your fingernails and hair for fuel, searching endlessly for another civilization, thousands of years between each star…
I’d probably spend most of my time trying to find a way to die.
THANK YOU! I’ll be here all week!
How so? Given the OP, my physical condition would be on par with the top n[sup]th[/sup] percent of the humanity, but I’d still be a lousy shot and prone to shell shock before too long. I’d also be reluctant to partake in an illegal war. I could still be captured, screw up, and do all sorts of stuff that wouldn’t work, especially because of my condition. Can you imagine being on a commando team with a guy who isn’t afraid of getting shot to hell? How is his risk assessment going to match up with yours? I’d be a terrible soldier, because I’d be getting everybody around me killed, since my risks are so much lower than theirs.
That just ain’t how science works. Cloistering a test subject in an insular community subject to group think isn’t going to provide nearly as much information as leaving me available for study by the wider world. I may have to hire body guards to get some people to leave me alone, and protect me from religious nuts who think I’m the Wandering Jew, but other than that, what issues will it really cause?
There’s just no benefit from the conspiracy thing. They know what caused it. They’ll spend a lot more time working on animal models than with me, trying to replicate the results with rats. Hell, when I was sick, my cancer was a super-tumor, growing at six times the normal rate. They took the tumor and never spoke to me again. Some tissue samples now and again, maybe an occassional test here & there, but otherwise what would they get from me?
::creeping up behind js_africanus, swiftly hides handkerchief doused in chloroform::
Wait a minute…are you telling me that you’re NOT the wandering jew? 'Cause I coulda sworn I saw you forging nails at this little shop outside Jerusalem when I was on my last time-travel trip.
What do you mean “if”?
I discussed this with my friends one time in college.
I would go to my girlfriends sorority and get invited to their formals year after year. In a hundred years, you would have a hundred formal pictures of me in their scrapbooks. Then one day I would take all the pictures, make a flip-book out of them where you would see me doing a clever dance.
That’s about it.
Why the fuck wouldn’t he just start swimming?
Wouldn’t chloroform’s effectiveness violate the conditions of the OP? (If Guinness no longer gives me a buzz, that will be sad. 
) Besides, you’re going to have a hard time keeping that cloth on my face.
Puleeze! With some of the religious nuts out there, somebody is going to be thinking that.
This has been tonight’s presentation of Amusing-Juxtaposition-of-Username-and-Post-Content Theatre.
Well, the OP did say “short of total vaporization.” If you are still on the Earth when the sun goes ker-blooey, I think that qualifies. So no worries there!