A new kind of electricity? 

You don't even have to bring private keys online to recover the funds. You could sign transactions offline and then publish them from a different computer.

So how exactly will Bitcoin help to "live forever"?

2030 is in just 19 short years. Any radical change would be quite a surprise. Even if he made a few sensible predictions over shorter time frames, "living forever" is in a totally different league from ordinary social progress.
What would be so good about it anyway? You'd just increase you're chances of dying an unnatural death. (Trans)humans cannot beat nature, they're part of it.

That's not a fair comparison, since most of the time-span, theoretically until 1971, the dollar was pegged to and/or backed by gold.
So these 2.5% interest would have been paid in gold for the majority of years. It's also no secret that gold inflates at ~2% per year because of mining.

I was generally referring to any fixed quantity currency, for example gold if gold mining would stop. A market economy and financial system would obviously help a lot. 

I'm still not 100% sure if saving currency is really equivalent to "investing in everything", with "everything" being a basket weighted inverse to relative prices?
Macro-economically the difference is obvious: the former would tend to raise demand for currency and lower demand for goods, thus being price deflationary (bust), while the latter would do the opposite and be inflationary (boom), but because of the fixed money supply and supposed perfect hedge, speculators can always even imbalances out and thus prevent boom and bust.

More realistic examples would have to incorporate cross border trade, which would create dependencies and invalidate conservation laws. Just as in physics, it's much easier to consider isolated systems, like an island or the whole earth, so I'll leave that to somebody else.

Let's assume the whole world uses a currency with 100% fixed money supply, e.g. Bitcoin in 2150.

Is saving these Bitcoins exactly the same as investing into a hypothetical basket composed of world stocks + real estate + commodities + ...?

I think yes, because both simply mean storing wealth by forgoing immediate consumption. Then traders should arbitrage away any changes in the demand for money, and this "world wealth index" should flatline. While real wealth increases or decreases, nominal wealth will stay constant. Bubbles in individual markets could still happen, but arguably smaller and/or less often.

Short term credit with negligible risk of default will be available for almost 0% interest rates.
Longer loans will reflect time preferences, which cannot be captured by simply saving cash.

This is an intuitive approach that a fixed monetary base is compatible with optimal economic growth, without redistributive effects.

What is the chart actually showing? Dollar in $ makes no sense to me.

@unk
I agree with you theoretically, and I always recommend holding only as much currency as needed for monthly expenses. If most people would do that, the central bank had less influence. But I don't think it's as easy as you make it out to be. We get bubble after bubble in things that seem to be good assets, but actually aren't. Gold is the only "hands-off" store of wealth, and in many countries it's legally impossible or expensive to acquire. In case of emergency it will likely get confiscated.

The main problem with central banks, fiat money and government debt is the illusion of wealth they create. When the economic distortions can no longer be hidden/ignored, people always blame scapegoats. For example the Greeks are angry at the prospect of becoming poorer, while, in fact, they were never as rich as they believed to be. Would you argue that there is no "debt supercycle", and that for example the US deficit is no big deal?

Nobody mentioned that this is LulzSecs public donation address?
Doesn't prove anything, but still interesting, no?

So if you're lucky, your account might contain a few hundred extra Bitcoins or dollars?

Site will open today at 3:00 GMT and trading starts at 4:00 GMT, that is in ~2,5 hours.

Not completely true, either.
At least according to the current code, the first block which does no longer award even a single satoshi, will be block 6930000 = 210000 * 33, mined in ~2140.

Where was Bitcoin in 2009?

The standard answer is that the most probable future value is todays value (efficient market hypothesis). However the market for Bitcoins is somewhat illiquid, and the EMH is controversial, anyway.
In Bitcoins case the random variable dominating all others is future adoption.
Current market prices imply lots of future growth, I would say about 100x. If people believe this growth will not be realized, prices will fall and if it looks like this growth will be exceeded, prices will rise.

They've reset the order book, and bitcoincharts show's the best bid/ask at 12.50/13.00, but no trade, yet.

So which is it? Of course it's neither proportional nor inversely proportional, at best it's loosely correlated.

But your main proposal seems to have merit. Simply said, there would be several "built in" derivatives, denominated in Bitcoin, which could be traded at different prices.

I just believe the complexity could put people off, as it makes Bitcoin even more difficult to understand. Why buy a financial system, if you want a currency? After all the things gone wrong in the traditional financial system, it would increase suspicions.
Also keeping the money supply predictable will be difficult: If an option might expire worthless based on a future difficulty, will it count towards the final 21 million or not?

You do realize that means, at least theoretically, complete user discretion over inflation?
It may even work, but it does feel kind of fragile.

Differences between exchanges are usually minimal because of arbitrage.
As to how MtGox will reset the price to 17.50, I have no idea.
If they intend to restore all bids and asks from before the crash, there will be a huge rush from people trying to change their orders and/or make a quick bug.

13.37

@Richard Andreassen

The problem with modifying supply based on an exchange rate is:
Which exchange rate to use? For example, when Bitcoin was created, there were no exchanges around.
It would introduce a lot of uncertainty in the design.

@BitCoinsForGold

Unfortunately you are in no position to control a peg. I can guarantee that you either won't sell anything or make a heavy loss.

Yeah, if they roll back trades, they also have to cancel all bids and asks.