Arduino Yun (1), Tessel (2), Electric Imp (3), Pinoccio (4), Spark (5)
(1) http://arduino.cc/en/Main/ArduinoBoardYun?from=Main.ArduinoYUN
(2) https://tessel.io/
(3) http://electricimp.com/
(4) https://pinocc.io/
(5) https://www.spark.io/
I've been experimenting with a Teensy 3 and an RN XV WiFly board. The cost is a bit higher than perhaps the all-in-one assemblies but they seem to come with strings attached.
If I'm going over WiFi I try to use OSC (or CoAP); basically the UDP path.
Next to explore is BLE. Then I have to look into 6lowpan.
One of my concerns with the items on your list is that they approach the Internet of Things as if it were little different than the Internet of Regular Computers. That is, HTTP or WebSockets over TCP, passing bulky messages, often requiring a central service to route every message. I'm skeptical this is the way to set up large numbers of small, low-power devices spread out over some distance coordinating with each other.
OTOH defining just what counts as IoT is tricky, especially with companies tagging everything as IoT because it sounds cool and hip.
I'm sorry I can't say much more about most things on your list. I've looked at them but as soon as I think it's tied to some 3rd-party service, or a special protocol, or HTTP-based, I lose interest.
(BTW if I'm wrong about any of them I'd love to know. But it seems they offer short-term gains in exchange for a certain product coupling.)
Teensy: https://www.pjrc.com/teensy/teensy31.html RN XV WiFly: https://www.sparkfun.com/products/10822
If you would like an easy way to get into BLE then check out the RFduino. I used it because it was the only thing I could find that would let me pass arbitrary data to an iOS device in an approvable app. It only took me a few minutes to get started with it, and they are cheap, but they have their own footprint, so shields aren't compatible with anything else.
For prototype any of the above is fine but for an end product keep production/supply chain costs as your primary concern. Your end product will look nothing like any of the boards that you shortlist.
Source: Worked at a Semiconductor company for years.
http://jeelabs.net/projects/hardware/wiki/JeeNode
They're basically a stripped down older Arduino (none of the built in USB or other new features of the newer Arduinos) with built in wireless (433 or 915mhz depending on your region), and the developer has done a ton of work getting them to be incredibly low power, mostly by working around some decisions made in the core Arduino libraries. He has had some running off of coin cells doing a test ping routine for more than a year now, if I recall correctly.
You'd need a gateway of some sort to get the data onto the internet proper, of course, but he also makes a usb dongle with the appropriate receiver, which you could plug into a raspberry pi or even a wifi router that supports USB serial devices.
POE would be nice for new builds where the cabling is not a problem but I don't think it is practical for anything you would want to retrofit into an existing residential structure.
If I had to bet, 6lowpan is probably going to be the winner in the wireless IOT fabric arena.
What microcontroller/board/etc is best depends totally on your application. Do you need low power, do you need processing power, do you need a significant web management interface?
I have chosen the STM32 ARM line and 6lowpan using atmel zigbee chips but your mileage may vary.
http://www.ti.com/tool/cc3200-launchxl
For $8 qty/1 you get: WiFi radio and IP stack and an 80Mhz ARM Cortex M4 with 200k of flash for your application. TI has great documentation and example code along with a dev. board for $29