Don’t get me wrong, I’ve nothing against Dropbox, I just know a lot of people use it.
If as Viv says you’ve nothing confidential on there, then it doesn’t matter. I’m of much the same view, and I’m currently evaluating a number of these services for personal use. I do grow very weary of the tinfoil hat brigade, but I think it’s worth making an informed decision (rather than an uninformed one).
It raises an interesting point though, if security is as generally lax as Samurai says. It seems that this is the way computing is going more and more at the moment, and it’s a short step from someone syncing a couple of holiday snaps, to them then making a recommendation at work that they do the same with all our financial data.