I ended up buying D&D4e on Saturday. Then went back Sunday to buy the Open Grave sourcebook, which contains the coolest monster ever. Unfortunately, I can't reveal it because all my players read my blog, and it's going to show up in a dungeon soon.
I spent most of Sunday figuring out how to build encounters. I think successfully, unless our first game ends in a total party kill.
And, in the process, I abandoned my original plan to build a massive three-level dungeon in favor of several shorter dungeons, generally two separate ones per character level. I think the 4e rules & monsters provide a lot of really great tools to construct some strongly thematic, evocative adventures. I ended up feeling like I'd be wasting a lot of that opportunity with a great big dungeon, even one consisting of various somewhat-themed components. For example, rather than a small shrine-crypt combo with a few undead encounters, I found I really wanted to build a very spooky catacomb under a desecrated church surrounded by a mist-filled graveyard of broken tombstones overgrown with moss & vines. And so I did.
I suppose I could have done all of this with the 3e rules, too, but for some reason I have yet to pin down, it just felt like 4e really supported those kinds of adventures, and fired up my imagination.
Now, does anyone know where I can find a writeup of a spider that, you know, spins a web, suitable for a starting party of adventurers?