Caveat -- Crises like the current one can wipe out even the best of portfolios.
If you look at government bonds (a.k.a. TBills), they'll tell you exactly how much interest a truly risk free investment is worth (in yearly interest). Anything higher then that is risky, by definition.
On top of that, you have to factor in inflation.
In other words, it's good to save money, but managing saved money is hard. Be ready for that.
That used to be true, but it isn't strictly true any more. The Credit Default Swaps for US Treasuries are priced to imply that you need to subtract around 1/10 of a percent (100 basis points) from the yield to get the real risk free rate. See http://www.fxstreet.com/fundamental/analysis-reports/sunrise...