Any astute reader out there.. use JAWR on your J2EE projects. It's fabulous. It just doesn't seem to play well with sitemesh (and I put the blame on sitemesh).
JAWR allows for properties-file-driven bundling + auto-minification (via YUI-Compressor [or your favorite, maybe]) of CSS and JS. It also supports a debug mode, which you can switch on with one variable change.
Know of a great .NET, PHP, or Python equivalent of JAWR? Please comment!