The phrase "game changer" is no doubt cliché and overused, but every now and again it just fits.
I had heard about Notational Velocity when Merlin Mann posted about it on 43Folders. It changed how I use my iMac, MacBookPro, and iPhone, bringing them all together in a very cool way.
The app has been around for awhile (we talked about it five years ago!) but some new features and new technologies make it well worth another look. It took me a minute to understand why I'd want Notational Velocity, it because it sounded like yet another "everything box" like Yojimbo, which I was already using.
Notational Velocity does save notes, either in ASCII, RTF, or HTML, but with the latest version, Notational Velocity syncs with Simplenote or WriteRoom for iPhone. It also easily syncs via Dropbox if you follow the important configuration notes here.
Imagine if Apple had created an over-the-air method of syncing Notes and it all Just Worked. That's what Notational Velocity has achieved. Notes on my iPhone, my iMac and my MacBook Pro. Edit a note anywhere, and the changes are synced nearly instantly and appear everywhere. It's fast, it's seamless. Thinking about getting an iPad? That's only going to make this setup even sweeter.