The conventional wisdom is that there was a housing bubble which has now popped. The data, however, tell a different story. Remember, that the evidence for the bubble was that real house prices had increased tremendously since around 1997 leading to prices that were far above any seen in the past one hundred years. Here's Robert Shiller's famous chart.
The clear implication of the chart is that normal prices are around an index value of 110, the value that reigned for nearly fifty years (circa 1950-1997). So if the massive run-up in house prices since 1997 was a bubble and if the bubble has now been popped we should see a massive drop in prices.
But what has actually happened? House prices have certainly stopped increasing and they have dropped but they have not dropped to anywhere near the historic average (see chart in the extension). Since the peak in the second quarter of 2006 prices have dropped by about 5% at the national level (third quarter 2007). Prices have fallen more in the hottest markets but the run-up was much larger in those markets as well.
Prices will probably drop some more but personally I don't expect to ever again see index values around 110. Do you? If we don't see the massive drop back to "normal" levels then the run up in prices should be described as a shift to a new equilibrium - much as happened during World War II - see the chart. (It's an important question to ask what changed and why?). In the shift to the new equilibrium there was some mild overshooting, especially due to the subprime over expansion, but fundamentally there was no housing bubble.
Here’s a nice picture from The Mess that Greenspan Made.