In keeping with the emerging consensus, Evernote seems to be the winner by default. I was hoping for something that would let me maintain a wiki-like structure the way I can with VoodooPad, but the only such animal I could find is TomDroid, which is an Android version of
Tomboy. Unfortunately, it's read-only (I guess they're working on editing support), and the desktop app is written in Mono, so you get an ugly, clunky UI without native app goodies like proper clipboard integration for pasting in images and other media. The only native Mac note taking app that has a decent Android counterpart seems to be Evernote, and though there are many things I don't like about it, it's probably as good as it gets for now.
I'm very pleased with Android so far, and the Nexus S 4G in particular. I still miss the keyboard, but I'm getting to be pretty proficient with Swype.
The one thing I don't really get is why I'm seeing a bunch of background apps running, including ones I haven't launched since my device booted. Tasker (which is awesome, BTW) pops up now and then to tell me my memory is low, and when I look at what's running, I see a bunch of apps that I haven't launched recently and shouldn't really be doing anything in the background. Why are they there taking up memory? I know the OS will kill them, but why do they run in the first place?