I had mine 30% in MtGox, 40% in blockchain.info, 30% in my offline walled (it's secure, but I'm always scared that I made a mistake & won't be able to recover the coins).
It worked great when coins spiked to $15 (I sold what I had on MtGox), and when the crash began (by the time I moved a part from blockchain back to the gox), so I sold the rest around $10.
Now I'm holding just the dollars, waiting for the price to stabilize or to get down to $5.