eM Client: A mail and calendar app for Windows desktop with full support for iCloud (Gmail and others as well)
I just started using eM Client for Windows. It's a desktop program that fully supports iCloud and sets up without any effort whatsoever besides logging in. You'll get everything: calendars, contacts, emails, reminders (if you change the default folder for creating tasks to "Reminders" you can create reminders in eM), and even access to the notes folder.
For iPhone/iPad users who own Windows computers, this is a great option (maybe the only option) for using your iCloud account on Windows.
Again, this is a desktop app, not a metro/modern app. It's a free download, or $50 for the "pro" version, which allows you to add more accounts in addition to other features.