If you don't mind running AD&D or you don't mind converting, Fate of Istus is pretty good. It is a bit rough around the edges, but that is one thing I think makes a good Greyhawk mod. It leaves a lot of room for the DM to toss in sidetreks to tailor the adventure to the PCs; that's what I did when I ran it. Plus, I can send you my 3e conversion notes if you want to try.
The original 3e WotC adventures are also a pretty fun "campaign path." Though they aren't as intertwined as Shackled City or Age of Worms, they are roughly contiguous and fit well into any campaign setting. If you run 3.5, you will have to update some of the stuff, but many ofthe monsters used have long been updated to 3.5 so you will have little work to do.
Savage Tides begins in Dungeon next month, so perhaps you might consider that one.
If Dungeon Crawling is your thing, then the World's Largest Dungeon offers enough material for a dozen campaigns! Contrary to popular thought, there is a storyline and it is fairly compelling. I have to say it isn't the most interesting campaign I've ever played in, but there is a lot to appeal to hack n' slashers, plus some pretty unusual roleplaying situations.
You could also easily build a campaign around Greyhawk Ruins (also from AD&D). Of course, perhaps you might just like to wait around until Expedition to Castle Greyhawk is released next year.
If you like Eberron, I've found the Eberron adventures to be pretty fun. The first three are a mini campaign of their own. Plus, the Queen with Burning Eyes from Dungeon #113 is a good prelude to start 1st level characters from. Our group had a blast with these adventures, though they will only take you to level 8 or 9, which is "high-level" for Eberron.
Well, that's a small list to get you started.
