Right now holding onto cash is probably the best bet. I'd expect deflationary pressures to continue despite the federal reserve's inflation. They haven't started dumping money out of planes yet but they will if the default rate starts to climb much more.
The rating companies who assign those AA and AAA are useless as well. Recently Moody's Investors Service threatened to lower Iceland's debt rating to junk. Why isn't it there already? It's absurd.
Right now I prefer to invest my money in business opportunities and hold onto as much as cash as I can. It seems like risk out there is extreme when interest rates are 0%. How can you judge what's actually going on in the economy when the price of money is so distorted? We're facing a serious shortage of capital right now and the notion that a 0% interest rate is the way to raise more is insane.
Anyway if these municipal bonds explode on you I don't think anyone is going to bail you out.