Start Menus for Windows
Here are the best 3rd-party Start Menus for Windows. If you miss the Windows 7 style Start Menu in Windows 10 for example, try one of these. You can easily show or revert back to the Windows 10 menu. Click the images to see larger ones.
For Windows 7, 8, 8.1 and 10. One of the original free Start Menu alternatives, Classic Shell does it all. You can choose a menu style, change skins and customize icons and links.
Edit: Official development of Classic Shell has stopped. See my blog post: Classic Shell for Windows 10 goes open source.
Start Menu X
For Windows XP, 7, 8, 8.1 and 10, Start Menu X is a customizable start menu which you can drag to resize. This menu makes it easy to find folders, files, and apps.
Start Menu 8
For Windows XP, Vista, 7, 8 and 10, Start Menu 8 gives you a clean and classic Start menu look. There are 3 main menu style options, plenty of customization options including transparency, and it's free.
For Windows XP, 7 and 8. Pokki is a little bit different in that it offers a modern style menu but has access to hundreds of free apps.
For Windows 10. With fully customizable backgrounds, textures and taskbar, Start 10 offers Windows 7, Modern, and Windows 10 style Start menus. There's a 30-day free trial and it's only $4.99 for the full version.
For Windows 8. StartW8 hasn't been updated since December 2014, but it works with Windows 8.
The Windows 10 Start menu is fine for me, but if you pine for the past, you can install these Windows Start menus (I recommend one at a time) knowing that if you don't like them, you can simply uninstall them and the Windows 10 Start Menu will appear and work normally.
Let people know in the comments which Start Menus for Windows you prefer, and why.