Ok so let's try to get some clarity around the various alternative formats and use sensible names for them now on - we can do a lot better than "Sam's GData XML" vs "My Simple JSON". Here's a few that come to mind:
AtomPub: Atom meets REST or "a simple HTTP-based protocol for creating and updating web resources"
CSV: Comma Separated Variable ala GoGrid, useful for reporting, asset registries, etc.
[X]HTML: Web interface for end users, optionally with semantic markup
JSON: JavaScript Object Notation or "a lightweight computer data interchange format"
PDF: Portable Documentation Format, useful for documentation and reporting