What is an adequate emergency fund?

The news is full of stories that we are heading into a recession so what constitutes an adequate emergency fund in such uncertain times? I have read that 3 months is a good cushion but I am pretty sure that 3 months is not nearly enough to keep you sleeping well in a full blown recession. Currently, I only have a little over a one month cushion in my emergency fund. I am fortunate to have a stable job but I still realize that one month is no where near enough.

Should I focus on my emergency fund at the expense of contributing to my 401k? My gut is telling me to continue to build both at the same time. Once I get a 6 month cushion (in about 15 months) I will save less cash and fully fund my 401k and Roth IRA. I believe my modified adjusted gross income will still be under the limits so I can still fully fund it in 2009.

In 2008 my budget calls for me to contribute $15,750 to my 401k and $1,200 to my Roth IRA. Saving for retirement and building my emergency fund are the two most important goals I have for the foreseeable future.