Stocks have just finished their first year of gains since 1999 - and most forecasters are calling for gains approaching double digits in the year ahead.
But what are the scenarios that could upset the bull market and what could keep it kicking in the year ahead?
Hefty hurdles lie ahead that could derail the upturn, analysts say. Higher inflation, rising interest rates and a slowdown in the rate of economic growth are all distinct possibilities.
A further weakening of the dollar is a near certainty, which could undermine US financial assets, including stocks.
But not all the surprises have to be bad. Companies have been so aggressive in cutting costs in recent years that earnings could prove to be surprisingly strong, analysts say.
Also, low inflation may very well prevail even with a rise in prices for oil and other key commodities.
And in an election year, the Bush administration is likely to push an economic agenda that favours stocks.
Last year, stocks rose despite starting the year facing war in Iraq and an economy that was rapidly shedding jobs.
The Dow industrials scored a gain of 25 percent - its best since 1996 - the Nasdaq average soared 50 percent and the Standard & Poor's 500 index jumped 26 percent.
Forecasters on average expect the Dow to rise 8.3 percent and the S&P to rise 8.6 percent in the year ahead, according to a Reuters survey of global strategists conducted last month.
Here are comments from top strategists who were asked what were the most important factors facing the market this year and where the stock market will be when the champagne is uncorked for 2005:
Philip Roth, chief technical analyst for Miller Tabak & Co, expects the leading averages to rise 5 percent to 10 percent and hit a peak for the year in the first half of 2004:
ROTH'S SCENARIO: "The first few weeks of the year are the best barometer for what will happen the rest of the year. A mediocre move up in the first couple of weeks or a move down would be negative.
"But if we have a couple of strong weeks in January that could be quite a different message. It would imply that for whatever reasons, investors are moving from bonds to stocks or to stocks from cash and stocks will keep moving higher."
Ned Riley, chief investment strategist of State Street Global Advisors, says we are in a long-term bull market that has several years to run and the Dow Jones industrials and Standard & Poor's 500 will both rise by about 15 percent in the year ahead.
RILEY'S WORRY: "The only real show-stopper would be a domestic terrorist attack, a successful one that clearly undermines consumer confidence and the capital markets, and clearly puts us in the box on the fundamental drive of the economy."
Hugh Johnson, chief investment officer, First Albany Corp, expects the stock market to have "a good year but not a great year" in 2004. He expects stock prices to rise about 8 percent, with the strongest performing stocks being larger capitalisation companies, a shift from the small caps that outperformed last year.
JOHNSON'S FEAR: "The dollar needs to be watched because ordinarily this big a decline in the dollar leads to rising inflation and interest rates as well as the possibility of a decline in stock prices.
The last time we had a decline of this magnitude in the dollar was in 1987 - and we all know what happened then,' referring to the Wall Street crash and record drop in the Dow.
Michael Metz, chief investment strategist of Oppenheimer & Co, sees the market already having exhausted the fruits of the economic upturn so that now "the best we can hope for is a flat year" in stocks.
METZ'S WORRY: "An inflation scare. There is a pervasive upward bias in price for housing and commodities and it could spread to end products. Manufacturers are having some success raising prices and the weak dollar helps them.
The surprise is that inflation rises significantly in the next year, pressuring the Fed to move rates higher. I would not be surprised to see the Fed move by March."
Peter Cardillo, chief strategist and director of research at Global Partners Securities Inc, sees the market moving about 10 percent higher in the year ahead.
CARDILLO'S HOPE: "There is a chance that we'll see a surprising escalation of growth to help the rally continue. With the cutbacks we've seen in corporate America, we've become leaner and meaner and now we have to see the profit growth continue - but we need to see profit growing from real growth factors and not just from cutting."
For the week, the Dow climbed 0.83 percent to 10,409.85 and the S&P 500 jumped 1.15 percent to 1,108.48. The Nasdaq rose 1.70 percent for the week to 2,006.68.