This is what I've basically gone with and I've had good results so far. I basically wanted the most return with the least effort, so I just went for index funds with the lowest expense ratios.

""" There are some potential advantages to the share class structure of the Vanguard S&P 500 ETF. Although VOO is only a fraction of the size of IVV and SPY, VOO offers the lowest expense ratio of the group, charging just five basis points. """ http://etfdb.com/equity-etfs/closer-look-at-sp-500-options/

I get that SPY is better if you need to liquidate millions on a moments notice, but I'm definitely not there, so the nearly-double expense ratio didn't make sense IMO.