This is a good idea. I don’t have the time to write the wiki article at this point, but I can give some tips on where to start.

For a local or development environment, xdebug can be very useful in profiling and exploring the application (http://xdebug.org/). Instructions on it’s use are located on the page, but you can capture nearly everything Magento does by putting xdebug start and stop functions around the run method in app/Mage.php. Varien also has a profiler that is already integrated and peppered throughout the codebase, that I haven’t looked into yet. It’s class file is lib/Varien/Profiler.php, and might be worth looking into if you don’t want to mess with xdebug.

As far as database profiling goes, if you are using MySQL, I knew a dba who was in love with Monyog (http://www.webyog.com). It’s a commercial product, but it has a trial version.

I look forward to hearing about people’s profiling experiences and the tools they use as we continue to explore and develop Magento.