Big spreadsheet advocate. I use spreadsheets for everything, basically my entire life is organized in a big excel file. All my finances, to do lists, notes, calendars, etc. Excel is flexible enough you can build almost any "app" inside it. Relevant to the OP, I'm using a CSV file right now to hold/organize the content for a website I'm building (it's highly templated, and in-framework templating seemed like a nightmare...easier to just generate the files out of a spreadsheet).
Similarly, I have known many people who use powerpoint for design work. UI design, interior design, even blueprints/architectural drawings. It just works, everyone already has it.
My wife just uses Excel like graph paper. She likes that you can write lists anywhere on the page. It's hard for me to watch but it works well for her.
How do you manage multiple TODO lists or projects within Excel? I notice that having many projects leads to many lists. For instance you can pile all of your tasks together, separate them by project, or by context. Triaging tasks and prioritizing across projects becomes a major undertaking by itself.
My question is not particular to Excel of course, but you seem like an organized person so I figured I'd ask.
Similarly, I have known many people who use powerpoint for design work. UI design, interior design, even blueprints/architectural drawings. It just works, everyone already has it.