While they are connected adventures, they aren't something you can set a full campaign around, which is the goal of an AP. You can (as I have) take several of these connected adventures and forge your own AP out of them by starting with the Temple of Elemental Evil, onto the Slavers, then Against the Giants, Descent, and Queen of the Demonweb Pits. The DL series, however, was completely intended to serve as a full campaign by running each adventure.Really? I would give that to Against the Giants/Decent into the Depths/Vault of the Drow/Queen of the Demonweb Pits.
The Slavelords sequence looks pretty much like a modern adventure path when bundled together too.