- The command line is much improved. Look through the properties to see what new options are available (text wrap, copy/paste, etc)
- If you're getting a laptop, pay a lot of attention to the trackpad. Windows laptops have a huge range from unusable to really good.
- If you're a developer you owe it to yourself to checkout the development tools like C# and Visual Studio, if only to set the bar for good tooling in your head regardless of what environment you actually program in.
- Check out the modern Windows 10 apps in the store. Mostly garbage but I regularly use and prefer a number of these to their web equivalents, e.g. Microsoft Groove, Netflix/Hulu, etc.
- When I got a PC, despite not gaming for a really long time I've gotten back into it. It's amazing how many wonderful games there are that are up my alley now-a-days, e.g. Broken Age, Firewatch, N++, Obduction, etc. If you've ever been a gamer, give that world another go.
- Get a great, high-dpi display. Windows support for it is fantastic and all those that say otherwise are crazy.
- If you're sufficiently nerdy and end up having a house full of Windows machines, you can invest in a dedicated server to handle things like a central file server and backup. Windows Server Essentials can make for a fun, accessible-but-still-nerdy project.
- If you're super concerned about privacy there's some reading to do to turn off all the new telemetry in Windows 10. I don't bother with this.
- Microsoft Office is best on Windows, and cloud support is better than ever. I enjoy using OneDrive and OneNote everyday on both my PC and iPhone. Give them another go if you gave up on them while using other OSes (Outlook on Mac is particularly awful).
- Windows is so fucking crazy keyboard accessible. Going back to using Windows involved me unlearning some of my bad habits from Mac.
- Windows 10 can be a little buggy in surprising ways. I had to reinstall at some point because the start menu broke. Seriously. And I tried really hard to fix it without reinstalling. Just keep backups and it should be fine, it's not way buggier than macOS or Linux, just older versions of Windows.
- Set "Developer mode" http://www.hanselman.com/blog/Windows10DeveloperMode.aspx (does a bunch of useful things like turning on file extensions in Explorer)