Should I roll over an old 401k into an IRA?

I have about 70k in a 401k from an old employer.
I'm currently unemployed, but I think likely to have a 70k/year-ish job in the near future.
What are the advantages/disadvantages to rolling over into a traditional IRA vs. a Roth IRA vs. just leaving it until a new employer's 401k comes along?