You can leave both your 401(k) and 457 Plan amounts in their respective locations until sometime before April 1, 2011. However, my answer depends on certain assumptions:

1) You are retired from both employers;

2) The companies where these Plans are located have not attempted to distribute your Plan balances (usually seems to happen within the first couple of months after leaving an employer), and;

3) You give yourself enough lead time to request the Lump Sum Distribution from each Plan properly (you should talk to each Plan's Administrator to get an idea of the MINIMUM time it can take to get your Distribution).

As long as you receive your Required Minimum Distributions no later than April 1, 2011, I am not really worried about the IRS taxing you for not taking enough out of your Plans in time.

Please don't wait until the last minute to ask the Plan Administrators to distribute - despite the fact that you in particular should be okay (they are typically required to make the Lump Sum Distribution within 1 year of you turning 70 1/2 anyway). Nevertheless, I am still concerned about company foot-dragging, even more so during a Recession!