Sony announced the Vita TV at their conference last night. Seems stupid amounts of cool for $100, comes with a DS3 controller (bundle pack is $150 and also comes with an 8GB memory card), you can play a good number of Vita titles on it as well.
"Outfitted with a PS Vita card slot, it also allows PS Vita TV owners to play Vita games on, well, their TV. They don't even need a Vita—just Vita games, this PS Vita TV hardware, and a DualShock 3. Oh, and a TV"
The thing that makes this a Day One, must have peripheral for me tho, having 5 TVs in the house:
"In the future, you will be able to use it to stream PS4 games on another television in your house via Remote Play."
The PS4 I get at launch will be hooked to our main home theater setup, but if my wife is watching something, I'd normally have to move the PS4. If I can just plug the VitaTV into another TV in the house and stream gameplay to it, this thing has pretty much paid for itself. I know it's not a big deal for a lot of people, but man, this is super exciting to me personally.
Also, you'll have access to any apps that run on the Vita, like Netflix, Twitter, Facebook, web browsing, Skype, etc.