I like separate devices, because the feature sets, prices, portability, and battery life are usually much better than all-in-one devices. Since I don't require 24/7 net access, I have more flexibility in choosing my gadgets.
- Phone: standard feature phone (calls, texting)
- Home: Kindle 4 (reading) -- iPod touch 4 (audiobooks, music)
- Traveling: Clip Zip (audiobooks, music) -- Galaxy Player 4 (GPS, internet)
The only thing missing is a 7" quad-core tablet w/ card slot. Primary use is for videos while on vacation (no wifi); after that, it's a toy.