I have them organized by room, but with outdoor temp and thermostats on the main panel. It just seems that when occupying a certain room, it makes sense to have all devices at hand. But with that said, I find it is just to inconvenient to launch the app, wait for it to synch/refresh, navigate to ‘things’ and then the room, in order to turn something on or off. Plus the integrations with Hue and the thermostats are kinda clumsy.
I ended up putting a number of frequently used ‘scene’ widgets on my home screens using either Hue or Tasker. These are things I usually run manually every day. If I want more granular control (for A/V gear, access to all lights, etc.), I use iRule, where I have a number of screens based on activity.
In the bedroom, most thing are all set by motion sensors and timers, but I do have a docked Nexus 7 on the nightstand (my clock radio so to speak) running @625alex’s ActiON, iRule, and have some Tasker/HAM Bridge ‘scenes’ triggered through ‘OK Google’ using AutoVoice for things I want to trigger manually (‘watch the news’, ‘listen to music’, ‘play a podcast’, ‘shutdown the system’, etc.). The goal is pretty much not to use the SmartThings mobile app for much of anything other than setup and notifications, and of course, control of things when I am outside of my LAN.