I like to have total control over my devices. I want the freedom to install and remove whatever apps I wish as well as the ability to install the operating system of my choosing. In addition to that, I want my smartphone to be of little distraction as possible. I use an open source launcher from F-Droid called Unlauncher, which itself is based on Slim Launcher. Unlauncher provides a visually minimalist interface. It allows for 8 custom applications on the home screen and an apps-drawer for the rest (which is what primarily differentiates Unlauncher from Slim Launcher).
I make it a point to have as little applications installed on my phone, and exclusively use free and open source apps - the majority being from F-Droid. The only notifications I get are calls, messages, and alarms (no email).
If you're looking for a clean and simple Android launcher with little distractions, I recommend 1) using Unlauncher, 2) removing and disabling all but the essential apps on your phone, and 3) turning off all but the essential notifications.
Update: I've updated my smartphone setup and have also gone more in-depth (described here). Unlauncher made some not-so-good UI changes, so I have since switched to Olauncher.Thanks for reading. Feel free to send comments, questions, or recommendations to firstname.lastname@example.org.