A guarantee that this thing was going to explode above $100 per coin, and at this point there are no guarantees, but I think many many people have a good feeling about the future of bitcoin.

I would first have to acquire this 'life savings' that supposedly has value.

One thing: asymmetric (inside) information.

Bottom line is that most people, as some have mentioned, don't really have this purported (or at least intended) "life savings" you speak of.  Aside of that, it's craziness to dump everything into one thing of value.  It's best to diversify.  But just to play along with your question, I'd have to think that first Bitcoin would need to be something that is relatively wide in adoption.

If I were to pour all of my "money" or "assets" into Bitcoin, would I be able to buy groceries of varying sorts in my city?  Would I be able to buy gas in my area and the places I travel?  Etc etc etc.

Until that scale of adoption occurs, dumping in and strictly holding to Bitcoins and away from any and all other currency assets of value, is illogical.

A time machine to go back two years.

As optimistic as I am about the future of Bitcoin, realistically my answer is "nothing"

Bitcoin is fail-resistant, but not failproof, and I can't risk my life savings on it because of that.

I'd never put all my eggs into one basket.

Head trauma.  I view this market as gambling.  If you view it as investment then remember what Mark Twain said, "Golf is a good walk spoiled..."

Wait.  Not sure that was the right quote.  Something about eggs and frogs.  Or baskets. 

Anyway my head hurts and I just invested my savings, mortgaged my house and maxed out my cards to invest in Bitcoins.  Little Johnny's education is on the line too.

Another, more serious answer:

http://images.sodahead.com/polls/001872937/5538361988_brass_balls_xlarge.jpeg

Already have.

It was only 20 bucks though.  At 1.80 each though, im sitting on a nice almost 1000% return!