I was actually thinking that the Arduino-related hardware probably deserves its own top-level page, rather than getting lumped in with tutorials about power supplies and burning bootloaders (tutorials about configuring Arduino-related hardware probably belongs there, though, like the one about retrofitting the Bare Bones Board for automatic reset). There used to be one at: Arduino Playground - SimilarBoards, which is linked to from the main Arduino hardware page. Maybe we should use that and link to it from the sidebar? Then we can rename the "Arduino Core Hardware" to something like "Connecting and Configuring Arduino Boards"?
And yea, there's no reason to recreate the list of the Arduino hardware in the playground when it's already on the main site. I actually removed it (piece by piece, really - I just kept moving its contents to places where they seemed more appropriate, and there was nothing left).