How to uninstall the "full stack" depends greatly on how it was installed as there are many options.
Here are answers with lots of assumptions on how you installed.
Drupal 7:
Delete the root directory of Drupal, most likely at ~/sites/
From the terminal - sudo rm -Rf ~/sites/
Delete the Drupal 7 database.
From the terminal:
mysql -u root; mysql> drop database ;
ref: How do I remove a MySQL database?
Stopping MySQL:
Answered here - How do you stop MySQL on a Mac OS install?
Stopping Apache:
In Lion, do the following:
To turn on Apache, go to System Preferences > Sharing and disable Web Sharing.
ref: https://discussions.apple.com/docs/DOC-3083
Later versions, do the following:
From the terminal:
sudo killall httpd
sudo launchctl unload /System/Library/LaunchDaemons/org.apache.httpd.plist
ref: https://superuser.com/questions/486966/can-i-end-all-httpd-processes-osx-10-7-4-lion