I remember that in DLD there was a session about this topic. The consensus was that Private Equity firms (or those that invest large sums of money) will get hit much more than VCs, and as a result the bigger the startup the more at risk you are. I also recall that Morten Lund claimed in the panel that a recession might prove to be beneficial (at least as far as Angels are concerned), because according to him, it will separate the great startups from the mediocre ones.
In my opinion, a strong recession, might cause valuation to go down, but it shouldn't affect early stage startup too much, because their backers usually look at a long term investment period.