This is a a pretty simple diversified, passive portfolio.

- VOO: tracks the S&P500 index (US large companies)

- VWO: emerging markets equities

- BND: US bonds

I picked these index funds because Vanguard ETFs are well-regarded for their quality and extraordinarily low expense ratios. For example, the much more well-known SPY ETF, which also tracks the S&P500, has an expense ratio of 0.10%. VOO has an expense ratio of 0.05%.