A lot of people do start companies during 'downtimes'. Off the top of my head: sixapart started when both Ben and Mena got laid off. Flickr was pretty much the same story IIRC.

Also could get one more attention -- maybe -- because the media won't necessarily expect anyone to be doing anything positive. Recessions are one big moan, and the 'yipee!' of a startup will stand in stark contrast. IMHG (in my humble guesstimation).