Perhaps Friday’s news that U.S. employers added 321,000 new jobs last month, well above economists’ expectations calling for 230,000 new jobs, will be the motivation investors need to reconsider consumer discretionary and retail exchange traded funds.

Ebullient economic data coupled with plunging oil prices should be all the cajoling investors need to revisit ETFs such as the Consumer Discretionary Select Sector SPDR (NYSEArca: XLY) and the SPDR S&P Retail ETF (NYSEArca: XRT). After all, as the Washington Post reported earlier this week, “Every day, American motorists are saving $630 million on gasoline compared with what they paid at June prices, and they would get a $230 billion windfall if prices were to stay this low for a year.”

Add to that, consumer discretionary and retail ETFs have entered their strong season period. Since 1999, its first full trading year, XLY has posted an average December gain of 2%. Yet none of that has been enough to stoke significant fourth-quarter inflows to XLY, XRT and rival ETFs.

Since the start of the fourth quarter, the United States Oil Fund (NYSEArca: USO) has plunged 27% while XLY, the largest discretionary ETF, and XRT are up an average of 9.1%. The Market Vectors Retail ETF (NYSEArca: RTH), the steadiest hand among major retail ETFs this year, has surged 12.2% this quarter, getting a lift from its 10.5% weight to Wal-Mart (NYSE: WMT). The world’s largest retailer is up nearly 10% this quarter. [Cheap Oil Lifts These Sector ETFs]

The importance of lower gas prices as they relate to the consumer discretionary sector, the fourth-largest in the S&P 500, should not be underestimated.