I want to preface this by saying I love Stock Android and am also unrooted. I have yet to find myself the need to actually root. However, my friends convinced me to try a custom launcher and at a time, icon pack. I decided to keep it pretty close to Stock however.
Anyway, here is my setup.
Launcher: Nova Launcher
Icon Pack: Stock
Wallpaper: Just one of the Stock ones. I've always really liked it since I got Lollipop
Widgets: Google Play Music widget, Spotify widget, Google Calendar widget, Google Keep widget, & Tasks widget (yes, I like widgets).
Basically I have three screens with Nova Launcher, but I keep it really close to Stock.
On the home screen, I have Google Play Music and Spotify widgets for music with the following apps: Fenix, Instagram, Reddit News Pro (free version here), Snapchat, and YouTube (basically my frequently-used social media).
On the second screen, I have my Calendar widget with the following apps: Feedly, Gmail, News360, Play Store, and Pocket (basically my news and organizational apps).
On the third screen, I have my Keep and Tasks widgets for to-do lists and things I need to get done.
The customizations I made to Stock using Nova Launcher are getting rid of the app text underneath the apps and changing the bottom mini display of the home screens from little circles to one line.
I'm probably going to look into getting some more customization going if I get bored and am considering upgrading to Nova Launcher Prime because it is a really nice launcher. I have only had my phone since Christmas so I am still experimenting with new customizations.