
I just received a 512 MB iPod Shuffle and after having it a week, I can say that, with a few modifications, I would be ready to replace my iPod Mini 4GB with it.
Re-read that last paragraph again. I'll wait. Done? Good.
Now, for those of you who don't know, the iPod Shuffle is a flash based, screen-less version of the iPod. It comes in two sizes: 512 MB & 1GB.