How aggressively should our generation save for retirement?

How about "fixed ratios are for idiots"? When you see that the stock market is dangerously high, and I don't mean by that that it declined for the last week, I mean something like the dot com bubble, where companies with the same earnings as a convenience store have a market capitalization in the billions, then it's time to transfer a part of what you own in stocks to bonds. Once the market is depressed and people are all saying "stocks are for idiots, bonds are safe", then it's time to actually buy the stocks, provided you can find good bargains, or buy an index fund. Mutual funds can be nice, but it's nearly as hard to find a good one as it is to find good stocks since a large number of mutual funds are crap. And those good ones are often closed to further investment.

Also, looking back in history, there have been times where bonds actually had better average returns than stocks. It hasn't been the case for some time now, but it doesn't mean it won't happen again. In fact, more likely than not, it will happen again someday.

I'll admit it, I have very little actual experience when it comes to investing, mostly since I'm only 18. However, there's one investment book I trust, partly because it makes sense and isn't a "make a million in a month" book, and partly because it has essentially remained unchanged since 1949, so there must be some truth to it. And if there's one thing I've learned from it, is that no type of investment is ever always appropriate. That, and an investor's worst enemy is himself.

Jam it back in, in the dark.