The first campaign I ran in 3rd edition was set in Greyhawk. We began with 6 or 7 players and "The Sunless Citadel" in early 2001. Other published adventures used included "Nemoren's Vault", "Thieves in the Forest", "Dungeon of the Fire Opal" (from Dungeon magazine) and finally "Return to the Temple of Elemental Evil" where the campaign cratered - twice.
The Sunless Citadel is not my favorite starting adventure. I think it's fairly dull and I dislike the main monsters at the end as they are oddball one-offs. Instead of ending with some kind of classic or iconic D&D beastie, we get an evil tree and it's stick-people minions - not my cup of tea. I did like the dragon hatchling included in the earlier part of the adventure and the NPC kobold Meepo. It can be fun to watch how different parties handle that interaction, and I think it's the best part of the module. Compared to something like Keep on the Borderlands it felt very limited overall. I give it a "C" on the traditional grading scale.
Thieves is a nice little sandbox area, good for dropping in on the way to somewhere else. It's not terribly overpowered, it's not stuck in one dungeon, and it's not tied to a plot hammer. Call it a 'B'.
Fire Opal is the ruined monastery map from the DMG1 fleshed out for 3rd edition. It's small but it includes a dragon and some interesting undead. My party liked it and I liked the old-school elements familiar from so many read-throughs of that map. I give it an 'A'
Nemoren's Vault is an interesting dungeon for low-level characters, more old-school in feel than Sunless Citadel. There's a tricky magic item in the dungeon that is unlikely to be found by a party but if it is it could be intrusive into a campaign. I planned to leave it vague and tweak it myself if it was recovered, but it never came up. The monster at the end is very nasty, probably too much so unless you have a large party of 3rd lvl PC's but it is a nod to a classic D&D beastie. I'd give this one a B+. The web supplement was fun for my party too, so look into that if you run this.
I will discuss RttTOEE in a separate post