Interesting topic, and I believe ShadowStich's post is the most intesting I've read in a while. That's totally what I had pictured (yeah, I do happen to think about that kind of crap when I'm alone at night
)
Now, to think about it... I think the situation would be incredibly cool.
On the one hand, you would feel extremely lonely and for the rest of your life. You would probably forget any language you know after a couple of years (unless you keep practicing and read books).
On the other hand, you would be able to go everywhere, see things you've never seen before, solve incredible mysteries...
You could go in government buildings and find out secrets (9/11, *cough* JFK)
The first couple of years of my life would probably be about finding a reliable, renewable source of energy. I wouldn't spend so much time caring about food because I would have canned food (food AND drink! woohoooo, unlimited everything!)
Then I'd spend time learning how to drive stuff like trucks, helicopters, boats, and eventually planes - not sure you can do that on your own though.
Anyhow, I would totally not be the type of person to jump off a bridge.