Does anyone out there still use D&D monsters by the book? I mean, are there still GMs that just use the stats as listed in a D&D clone's monster section without any changes?
In this age of cheap PDFs that players can obtain all too easily, most players will have their own copies of game books. This is a significant change from the early days of the hobby, correct? Back in the day, it was really only necessary for the GM to own the books. Now, more often than not at least one player has a copy of the rules. Add to that the fact that long-time players can recognize creatures from when they played the game years ago, and you have some pretty knowledgeable players.
I know what you're thinking: this all ties into the "player vs. character knowledge" argument. But how often are players going to say "my character wouldn't know what a basilisk is, so I'm going to walk right up to that giant lizard thing and stare it down"?
No matter how good a player may be, he or she is definitely going to make their plans on how to "conquer" a creature based on what they know, and not what their character knows.
The answer? Well, as you've no doubt read on many a gaming blog, you need to create variations of old monsters that bring something new to the beasties. A monster that has different abilities than the by-the-book version is a nice surprise!
So, what sort of variations of classic monsters have you encountered/inflicted on your players?