This chart has been continually updated over the past several months by dshort.com. It contrasts our current economic downturn with the Great Depression, the 1970s Staglation/Oil Crisis, and the DotCom/Tech Bubble Crash. (HT: CalcRisk)
Curiously, there aren't a ton of comparisons. I've been looking at this chart over the past couple months, trying to see if it offers some predictive quality, but none is available. I find this interesting on one hand because it could be theorized that, given a perfect market structure, recessions would take a similar form in clearing the market every so often. But the political scenarios of these four economic crises were all different and impacted in different ways. It would be fascinating to plot government interventions onto this chart and see what the lag time was in impact (though establishing causality is always very tricky and loose).