Anyone who's been paying attention knows that exchange-traded funds are the latest hot thing in the investment world. The number of offerings and total assets in ETFs has exploded in recent years. In fact, more than 200 brand-new ETFs have hit the market in the past year alone. Most of these new ETFs are either leveraged and/or inverse funds or funds that focus on a single sector of the market. I don't believe most investors need pricey, narrowly focused ETFs like these, so you can probably safely ignore the majority of new funds coming onto the market. However, there are a few new ETFs that are worth a second look.

Schwab Emerging Markets Equity ETF (NYSE: SCHE)
This ETF newcomer is only about seven months old, but it looks like it could be a promising addition to the emerging-markets fund category. Schwab Emerging Markets ETF tracks the FTSE All-Emerging Index, which consists of mid- and large-cap companies in developing countries. This fund comes with a low 0.25% expense ratio, just a hair below one of the more popular emerging markets ETFs, Vanguard Emerging Markets Stock (NYSE: VWO) with its 0.27% price tag. The Schwab ETF also offers a significant price advantage over the largest emerging markets ETF, iShares MSCI Emerging Markets ETF (NYSE: EEM), which clocks in with a 0.72% expense ratio.

When it comes to ETF investing, costs are key, so investors really want to go for the lowest-priced fund they can find. Since you're not paying for the expertise of the fund manager, why fork over more of your money to track an index? That's what makes this new ETF so appealing: If it can undercut the competition by even a small margin, it could outperform, attracting a lot of assets in the process.

Schwab U.S. Broad Market ETF (NYSE: SCHB)
Schwab has really been going for the jugular lately, cutting commissions and expenses on its proprietary lines of exchange-traded funds to capture market share. The Schwab U.S. Broad Market ETF is no exception. This fund was launched last November and so far, short-term performance has been promising. Since its inception, the fund has posted a 3.4% gain, compared to a 1.8% showing for the S&P 500 Index. This ETF seeks to track the Dow Jones U.S. Broad Stock Market Index, which is a wider and more inclusive bogey than that of the SPDR S&P 500 (NYSE: SPY). That means you're getting wider market coverage and more diversification for your investment dollar.

The Schwab U.S. Broad Market ETF comes with a super-low 0.06% expense ratio. That just edges out one of my favorite broad market ETFs, the Vanguard Total Stock Market Index (NYSE: VTI), which costs 0.07% a year. Both are top choices for getting wide market exposure at a low cost, and both have pretty similar portfolios. Again, the price differential between the funds is not that significant, but over the long run even a minor savings could add up. In a world of sector-specific and leveraged funds, this Schwab ETF stands out as a reasoned choice for any investor.

Vanguard Intermediate-Term Government Bond ETF (NYSE: VGIT)
Lastly, bond investors who are looking for a bit of a safe harbor may find something to like with this new Vanguard ETF. This fund tracks the performance of the Barclays Capital U.S. 3-10 Year Government Bond Index. Year-to-date, the fund has posted an impressive 9% return. Clearly returns won't always look that good, but for investors who want the safety of Treasury bonds with a slightly longer duration, this fund is a good choice. With its 0.15% expense ratio, you certainly won't go broke investing here.

This fund isn't a direct substitute for a broader market bond index, since it excludes corporate, foreign, and mortgage securities, but it is a low-cost way to get targeted exposure to government bonds. Investors should be aware that the fund could be hit once interest rates rise, but given the current economic soft patch, rates are likely to remain low for some time to come. And given the anemic yields on short-term bond funds, investors can get a bit more juice by moving out slightly on the yield curve to a high-quality fund like this one.

Ultimately, investors should be skeptical of the vast majority of new exchange-traded funds that have been hitting the market recently. While investors can safely do without almost all of these offerings, there are a few attractive, low-cost options that could function as a reliable anchor for any investor's portfolio.

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Amanda Kish is the Fool's resident fund advisor for the Rule Your Retirement investment newsletter. At the time of publication, she did not own any of the funds or companies mentioned herein. The Fool owns shares of Vanguard Emerging Markets Stock ETF. The Fool has a disclosure policy.