If you strain, and think back to the (no doubt MANY) Dungeon Adventures you've played in and/or run down through the years - whether purchased (or indeed home grown, I've read some amazing unpublished dungeon-centric adventures).
What makes a Good Dungeon-Crawl Good? (or hopefully even Great). What makes a Dungeon an enthralling place to explore and adventure in - a suitable environment to "Fight the Good Fight" - rather than it being some boring repetitive exercise in monster bashing and door breaking . . . .
1- A Goal
The PC's need a reason to be there (outside of the obvious Treasure and Glory). A mission - often one of the three "R's" (Rescue, Retrieval, or Revenge).
2 - A "Hook" or Theme
Its important that the Creatures/Monsters have a common link - Whether it be they all work for a Villain, or come from the same (or related) families of Monsters.
3 - Style or "The Look"
When describing the environment, remain consistent. If its Medieval, keep the descriptions as such. If its Egyptian styled, don't start throwing in Renaissance Torture Chambers in - suspension of disbelief is really important during FRP games - if you break from your internal consistency, you can ruin it for your players.
4 - Pacing
DO NOT allow your players to pause for breath, keep the descriptions coming - and the encounters rapid. The minute they finish with one problem, introduce another. It seems a daft thing to mention, but the more you keep your players on their toes - the more they will enjoy it.
5 - Traps, Tricks, and Puzzles
A lot of modern DM's don't like including Traps, Tricks, or Puzzles - they find them trite or old fashioned. BUT when a Player beats/circumvents such an encounter they will be bouncing with excitement MORE than if their Character had slain the biggest of Dragons.
Here is a list of some great books to pic up for reference, all are useful and are non system specific so any DM can get good use from them.
Central Casting Dungeons
A dungeon random-generation kit, with piles of very specific details. Great if you want to generate random (although illogical) dungeons. Now out of print (Originally Published by Task Force Games), if you search around you can generally find it somewhere to Download.
The Dungeon Alphabet
Billed as an A-to-Z Reference for Classic Dungeon Design - The Dungeon Alphabet compiles twenty-six classic dungeon design elements in one place to assist the game master in creating subterranean challenges. A is for Altar, B is for Books, and C is for Caves and so on. Its one of my all time favourite books. The Dungeon Alphabet is available in both Print and PDF format - produced by Goodman Games.
Similar to Central Casting Dungeons, but more streamlined and logical is Engineering Dungeons from Troll Lord Games. Though formatted for Castles & Crusades its easily usable with any edition of Dungeons & Dragons (even the dreaded 4th Edition). Engineering Dungeons brings the DM the tools to entice the imagination, to create, wholesale, from scratch, a varied array of dungeoneering experiences. You will find the means to determine monsters, their treasures, their lairs - who, where, and why a dungeon exists, and even flavorful aspects of the dungeon environment, such as light, air condition, and odors. Traps, of all sorts, designed to function as a universal difficulty system, are included.