The word "forever" means different things to different people, but in this case, I really do believe that these six ETFs could be purchased for a long-term portfolio and never sold. The fact is that the sectors and/or industries that these ETFs represent should form the absolute rock-solid core of any diversified portfolio. And yes, I hold them all in my portfolio.
PowerShares Dynamic Oil & Gas Services ETF (PXJ) is an important play for me. I like holding the big oil producers like ExxonMobil (XOM), Chevron (CVX), ConocoPhillips (COP) and BP (BP) for their solid dividends (2.4%, 3.1%, 3.8%, and 4.2% respectively), but I want to be invested in the guys who sell the picks and shovels, not the ones mining for the gold, if you know what I mean. You get a basket of stocks including Rowan Companies (RDC), Weatherford (WFT), Transocean (RIG), and Baker Hughes (BHI). These are the juggernauts of oil services, they are financially solid, and will always be needed since oil will always be needed.
Consumer Staples Select Sector SPDR (XLP) is a must-have because consumer staples are, by definition, must-haves. In good time and bad, people must have their cigarettes [as represented by Philip Morris International (PM)], soda [Coca-Cola (KO)], and snack foods [Kraft Foods (KFT)] along with the things sold by Proctor and Gamble (PG) and Wal-Mart (WMT). The ETF also pays a 2.89% yield.
Precious metals may seem expensive these days, but over the very very long term, they will remain precious. There are both industrial uses for them as well as storehouses of wealth. That's why I hold SPDR Gold Shares (GLD) for the yellow metal, and ETF Physical White Metals Basket Shares (WITE) for the white metals: silver, platinum, and palladium.
Utilities are a necessity of life, so the iShares Dow Jones US Utilities (IDU) offers exposure to domestic utilities, avoiding the uncertainty with foreign stocks. I'm very comfortable holding an ETF which boasts The Southern Company (SO) as its largest holding, and stalwarts like Dominion Resources (D) and Duke Energy (DUK). It also pays a 3.66% yield.
Finally, there's no surprise that I suggest you hold an ETF for the broad market, but go with the Wilshire 5000 over the S&P 500. Wilshire 5000 Total Market ETF (WFVK) will provide that Tootsie Roll center to your portfolio Tootsie Pop. A 1.46% yield never hurts, and you'll have comfort in that diversification.