Reasonably salted hashes are next to impossible to crack (reverse).
Unfortunately this is no longer true. Salting is an affective defense against rainbow tables, but there are new tricks in the bag: a single graphics card can try several billion vBulletin salted passwords per second and you can have several cards in a single machine.
In general salting is almost pointless if the attacker can obtain the salts (and typically they do, they're in the same table as the password hashes). Salts of course do raise the amount of work required for cracking but the GPU grunt has leveled the field again.
The solution is to use multi-round hashing of the password + salt.
