I'm installing IntelliJ, and the readme tells me to choose an installation folder. Where is a good, standard place to put installed programs?
Where should I copy-paste-install software to?
software installation;directory structure;intellij
If you are the only user of it, just slap it in /home. If not, /opt/intellij. Avoid /usr, which should only be used by distro-managed software. Many source installers use /usr/local by default, but the advantage of /opt/intellij is that you can wipe the entire directory if you no longer have a use for it. Putting it under /usr/local, the stuff would get distributed all over the place, adding the need to track where those are installed; there's tools for that, but don't  bother. Any decent installer should create all directory structures for your installation to work, wherever you choose to install to.