For hardcore note-taking junkies, Evernote is a tough app to beat. The service gives you multiple notebooks into which you can save text notes, complex lists, images, and voice reminders. You can even send content into an Evernote notebook by emailing it to a special address connected to your account.
Evernote keeps your stuff synced with its own service. It's accessible on the Web and on most major platforms, so that setup tends to work well enough.
Evernote is free, though certain functions -- including offline access, advanced searching, and increased transfer allotments -- require a $5/month or $45/year premium subscription.