I highly recommend a visit to Mish's Economics blog.
It contains a very good and detailed account of just how long it might take before the US reaches the under 6% unemployment rate enjoyed in 2007 - and the results are NOT PRETTY to say the least.
Given the sheer drop in employed, and the trend in recent recessions for job losses to continue well past the end of the recession, Mish takes the long view and projects unemployment to 2020. With a set of what I believe are realistic projections, he concludes the US will not see 6% unemployment in the next decade. Period.
His report also includes a downloadable spreadsheet to play with the figures - essentially, we would have to create 150k jobs per month for the next ten years - without recession - to get the unemployment rate to 6% in 2020!
I won't repeat his analysis, suffice it to say, it is scary - and what if (as I believe likely) this turns into a double dip recession as the governments around the world find themselves with impossible fiscal situations and begin a process of cutting outlays and raising taxes - with more job losses rather than job gains?
Thanks to John Mauldin for pointing me to this.