I wholeheartedly believe in this fourth tip of Forbes ten rules for building wealth of not trying to beat the market. Honestly, you have better things to do with your time than research investments and you should be doing those, instead of checking PE ratios, growth rates, and the like.
Strangely, Forbes focuses a lot on asset diversification and portfolio balancing in this tip and a little less on convincing a reader to go with some index funds. While I think the underlying idea is that you go with funds anyway (building on the idea of keeping things simple), they don’t make mention of it in this particular tip.
One tool that they mentioned that is worth checking out is Morningstar’s free Instant X-Ray tool.