That's all fine-and-dandy if you can manage the risk.
It is also a good way to get bitten.
More evidence for you, chodpaba, suggesting MtGox is losing quite a bit of volume...the total number of bitcoins for sale is lower than I've seen it in months. And I'll offer my own anecdote. I no longer have any USD or Bitcoin in MtGox at all. Nothing against MtGox. I think it's one of the best bitcoin institutions right now, but I've recently moved from a trading mentality to one of saving and using bitcoins. My great wish is that I'll never need to trade my bitcoins back into fiat currency and that eventually (I'm talking many, many years) I'll be able to easily buy most of what I like to buy with bitcoins instead of fiat.
My current position is that it's better to buy bitcoins at any price rather than speculate - if the price goes down, buy more.
I chickened out with many of my bitcoins at $4.20 and then moved the $s to Bitcoinica - I could have kept them safely encrypted on my computer and just bought more to mitigate any dip in price.
Instead I'm now waiting in limbo.
I guess I should have added that in addition to saving and using bitcoins, I'm also accumulating more. Though, like you, I regret not doing this more over the past few months. For a while I was accumulating some from buying back after sells I had made since the $7.2x top, but I hadn't put much new money in until a few weeks ago and I plan to buy some more in the coming days. I definitely feel better now that my bitcoins are out of the exchanges and in offline and physically backed up wallets. I was stung a little from this bitcoinica debacle, but thankfully I had enough good judgement to not put very much in there, though it'd be nice to get it back.