And remember that hashing the passwords is, in actuality, a sort of last ditch layer of security, and arguably of minimal use. Such hashing only comes into play if your database has become compromised and someone is therefore able to view the passwords stored within it. If your site's security has been compromised to that degree, there's a good chance that password revelation will only be one of many problems you are going to have. Even if the hacker cannot crack them (or doesn't want to take the time to do so), if he has access to the database he may well be able to add/delete/modify other data in it which may end up being a lot more harmful. And if he has gained access to your database, what else has he gained access to?
I'm not saying to forget about hashing passwords, but not to count on that as a good way of securing your site. Rather, consider it to be a fairly minor layer in what should be multiple layers of security on your site.
