I use my iPod touch to:
1. Control my lights (Hue)
2. Control my TV, Receiver, Apple TV, Blu Ray and Cable box (Unity Remote)
3. Control my thermostat (Nest)
4. Use it as a remote control for my TVs(Comcast) and iTunes library (Remote)
It sits on a dock in the living room so it's always charged and within easy reach. I can use my iPhone or iPad for these things, but I like having one dedicated device for all of it, that does not leave the house, as some of the programs I use require it not to be disconnected without going through a reconnect. I subscribe to iTunes Match so I don't need a specific device just for tunes, with the exception of my motorcycle as it's integrated into my helmet and bike.
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iPhone 5
MotoX
iPad Mini 32GB
Macbook Air
Apple TV 3rd Gen
iPod Touch 3rd gen (remote control)
iPod Nano 6th Gen (watch)
iPod Shuffle 2nd Gen (motorcycle)
iPod Click Wheel 5th Gen (alarm clock)