Whats the difference between a recession and a depression?

So, what is the difference between a recession and a depression? The old joke states: "A recession is when your neighbour loses their job. A depression is when YOU lose your job".
On a more serious note, whilst there is no agreed definition, a depression may be defined as a recession where real GDP falls by more than 10%. The last one in larger developed economies was the Great Depression of the 1930s, where unemployment in Australia got to 20%. Recovery from this was patchy, with another less severe depression during 1937-1938.
Normal economic activity did not return until 1940-1941. Since then the US has not had anything close to a depression. The worst recession in the last 60 years was from November 1973 to March 1975, where real GDP fell by 4.9 percent. 

Given the sober global outlook for 2009, Perennial’s latest projection is that our economy will have a mild recession with the second half of 2009 starting to see positive growth returning.

The experts are saying Year-on-year GDP growth for 2009 should be just positive (could possibly turn out to be slightly negative), with positive growth for 2010. Therefore, the view that this is NOT a depression. Whilst we believe unemployment may hit 7% at its worst, with 93% of Australians still employed, this is not near depression levels.
So, don't read too far into the media who suggests we are going to see unprecedented job losses, and all is doom and gloom for years to come. There is some hope in the near future.