User Activity Report

Hello,

I am looking for the best way to capture a full user's activity. Not just when the logged in, but when they've made an "action" in the system. This includes but is not limited to commenting on a task/project, "working on" on a task, completing a task, commenting on a document, etc. An hours report isn't 100% accurate because we have some users who aren't consistent with logging their time. I've also tried a task report but there are some times when a user is dual assigned to a task and it pulls in the task even when the user didn't actually action on it. I've tried a User report but that reporting doesn't seem to have the criteria that we need. Any suggestions would be appreciated - thanks!