I actually wrote about Wunderlist, an up-and-coming to-do list manager, in this column around 18 months ago. Since then, it has progressed in leaps and bounds to become a very useful and well-known product.
At its heart it's a very powerful list manager. Use it to manage your to-do list, shopping list, project tasks, or just about anything else. It looks great, is easy to use, and you can share lists over the cloud. It's free to download and use, although you can pay extra for the Pro and Business versions if you really want to. It comes as an app for iOS and Android, and is also available as a Windows 8 app (metro style) and a Windows 7 application (desktop style). If you prefer traditional desktop programs to modern apps and you happen to run Windows 8, just download the Windows 7 version - it'll work fine.
Naturally, all the apps and programs work together via your Wunderlist account (which you'll need to set up - it's free). So your lists are available on all your devices, wherever you happen to be.
The Windows 7 program is a 42 MB download from https://www.wunderlist.com and the program is malware-free according to VirusTotal and Web of Trust. You can even create public lists which are available to anyone who wants to download them. Just make sure you don't make your private lists public, though!