Talk about a tough Fool Awards category. Coming up with candidates for the biggest opportunity of 2008 isn't easy when it felt like the only opportunity investors had was to lose money.

But throughout the year, we've looked for silver linings in the bear market. And while the vast majority of stocks fell in 2008, there were a few bright spots. So, without further ado, here are five nominees for your voting pleasure.

Discount retailers
For companies that offer low-cost alternatives on necessities like food and clothing, a struggling economy is actually a good thing. Discounters like McDonald's (NYSE:MCD), Wal-Mart (NYSE:WMT), and Family Dollar (NYSE:FDO) all posted gains in a losing market thanks to a growing base of budget-conscious customers. Investors who foresaw the recession got a nice reward.

Short selling
After years of taking it in the shorts, short-sellers finally got their revenge in 2008. Popular bear-market ETFs delivered amazing returns as stock markets tanked. And for those who bet against stocks like Sirius XM (NASDAQ:SIRI) and General Motors (NYSE:GM), the profits were especially sweet.

Cash
With interest rates at historic lows during much of the decade, cash got a reputation for being a waste of investment capital. Not so during 2008, though, as the credit crunch made having money on hand attractive again. While liquidity-starved companies suffered to raise capital, cash-rich giants like Berkshire Hathaway (NYSE:BRK-A) (NYSE:BRK-B) swooped in to pick up assets on the cheap.

Tax-loss selling
No one ever said losing money was fun. But at least it'll give you a break on your tax return come April. Yes, in portfolios full of red ink, the best many investors could do to salvage something amid the carnage was to sell and grab valuable capital losses to offset past gains and other income.

Stocks
Wait a minute -- stocks did terribly in 2008! Yes, but for those still looking to buy stocks both now and in the future, lower share prices meant more bargains for value-conscious investors. Although you may not see quick gains on shares you bought last year, cheap stocks may prove to be the most valuable long-term opportunity you could find in 2008.

But that's just one opinion. What do you think was the biggest opportunity in 2008?