I would suggest something that is web based.
So as long as you are online, and browsing (which is something most of us do naturally without fail), it would be up there in your browser.
This is what I use:
- The app/software - Any.Do
- Browsers - Firefox/Chrome
- Platforms - Any PC platform with browser would do, PLUS, Android and ios devices.
The benefits are as follows:
- Any.Do is one of the leading software/apps for to-do lists and reminders.
- It is integrated with Cal (another calendar application by the same people) and Google Calendar, as well as Gmail. Integrations are extremely functional and powerful.
- In browsers these days, you can make your own accounts with settings and extensions and so on. So if you download Any.Do extension in your browser account, you can basically have the same setup along browsers on both systems.
- Since this works on mobile devices as well, not only would it give you reminders in your browser/email integration but will also give you notifications via your mobile device.
The implementation and setting up is a one time step and after that I am pretty sure your to-do lists and tasks can be managed easily.
Best of all, its FREE! :)