if you believe the Fama and French academic research that small does better than large, and value does better than growth, following is a list of ETFs recommended by Paul Merriman.
http://portal.paulmerriman.com/home/mutual-fund-etf-recommendations/Fund Symbol Aggressive Moderate Conservative
Schwab U.S. Large Cap SCHX 11% 6% 4%
Vanguard Value VTV 11% 7% 5%
Schwab U.S. Small Cap SCHA 11% 6% 4%
Vanguard Small Cap Value VBR 12% 7% 5%
Vanguard REIT Index VNQ 5% 3% 2%
Schwab International Equity SCHF 9% 5% 3%
iShares MSCI EAFE Value Index EFV 9% 6% 4%
Vanguard FTSE All‐Wld ex‐US SmCp Idx VSS 9% 5% 3%
WisdomTree International SmallCap Div DLS 9% 6% 4%
Schwab Emerging Markets Equity SCHE 9% 6% 4%
Vanguard Global ex‐US Real Estate VNQI 5% 3% 2%
iShares Barclays 1‐3 Year Treasury Bond SHY 0% 12% 18%
iShares Barclays 3‐7 Year Treasury Bond IEI 0% 20% 30%
iShares Barclays TIPS Bond TIP 0% 8% 12%