Finally deleted my Instagram account, after letting it lie dormant for half a year. Facebook makes it _really_ hard to delete an Instagram account (their last site that's actually gaining users, I'm sure):
1) You can't delete it from the app
2) There's no UI or link to delete it through the web interface
3) You have to Google "how do I delete an Instagram account", that leads you to a page using an _old_ UI that looks like it's out of the iOS 2.0 web app days: https://instagram.com/accounts/remove/request/permanent/