Just a quick note, as you may notice from the comments, Magerun now pretty prints the xml output by default. It appears DomDocument requires preserveWhitespace = false in order to correctly reformat output. Thanks to Christian for sorting it all out!
I'll be writing about how awesome Magerun is shortly, but just one of its cool features is the ability to dump out a merged version of Magento's config.
This is extremely helpful when trying to resolve conflicts between modules, or figure out what bit of configuration is taking precedence.
The resulting xml though is pretty raw and unformatted, but xmllint can fix that.
Xmllint expects a file to work with and cannot use piped input. So we need to use bash's Process Substitution feature to avoid having to create temporary files.
$ xmllint --format <(magerun config:dump)
So, magerun and xmllint, a simple way to get a formatted, easy to examine view of how Magento is putting your install's configuration together.