I have used a couple of the 4th edition books (series linked above) as well as the older 3rd edition book.
In fact, I ran a really great "Monster Of The Week" modern horror campaign in which weekly prep consisted of flipping through the 3e book and finding something that looked like fun.
Each monster is more than a collection of stats, though. You'll get an adventure seed, some information on the motives, lifecycle, or other background on the creature, and sometimes variants, or ways to re-skin monsters for various campaign types.
I don't have the books in front of me right now, but I can tell you that the books present creative and interesting new monsters and beasts. For example, I remember an alien creature that mimics a house and feeds off of the misery of residents (this was way before Monster House, btw) which I used to great effect as a haunted house in a Buffy or Changeling game (I can't remember right now).
In other words, you're not going to get a thousand different kinds of orcs, you're going to get well thought-out creatures that you'll have fun pitting against your players.
I don't play much in the way of dungeon-oriented games, but these books are my go-to resources for monsters in pretty much ANY game.