[Hell Puppy]

I use pennywize, totally seamless to the user, doesn't make them jump thru any additional hoops to get in. And although it doesn't prevent people from sharing the password, it ensures that they get very little usage out of it, and I get alerted that it's being done. It also prevents them from ripping the entire members area if you so desire by locking them out after a defined amount of data has been transferred.