caveat emptor

Not all funds labeled "index" are actually a good choice.
Some "index" funds charge a gigantic 1.5% or more in management fees.

So it is not done just learning that "index" - funds are good, you still have to look out and study closely all the cost of each fund you are contemplating adding to your portfolio.

Below some examples of "index" - funds, and the costs occurred by the investor:

index tracked  "good" funds / ETF's  "not so good" funds  difference in costs  
S&P 500  IVV (iShares) = 0,09% Pictet US Index = 0,2%   CDC US Equities Indexed = 1,5%  at last 1,3% (last updated feb. 9th 2004)  
SMI  Pictet Swiss Market tracker = 0,2% XMTCH SMI = 0,35%   EMIF - Switzerland Index Plus = 1.15%  at last 0,8% (last updated Feb. 9th 2004)  

note*: the above list was edited to our best knowledge and on the dates indicated.
The list is not final, as the funds and the available information shift often and unannounced.