Big Picture doesn't throw the kitchen sink into the mix, but it does offer some nifty features and it's only going to grow in the future as it's developed further. There's a new web browser, a Daisywheel to type with your controller and more.
The Web Browser
I found the web browser to be a great addition to Big Picture mode - and not something I would use as a main source of web browsing as I have Windows running in the background. But I can see where Valve is going with this - as it's mainly destined for the TV. The user interface is perfect for it, and it is built from the ground up to support a controller for navigation.
The included web browser sports a reticle-based navigation system, tabbed browsing and saves your favorites from the browser into Steam's cloud.
This is one thing I couldn't test as I don't have a wired Xbox 360 controller, or any other controller for that matter, to use with Steam. Valve have explained Daisywheel as "QWERTY is for keyboards. Daisywheel is for controllers". This sums it up quite well.
Daisywheel is Big Picture's tool for typing and looks pretty good judging from what I've seen - hopefully we can get this tested in the near future with a controller.
Multiple input methods being on offer only extend Valve's awesomeness more so. Want to game with the traditional keyboard + mouse setup? Go ahead. Want to game with a controller? Go ahead. Want to do both and switch between? Sure!
The usual suspects
The usual features of Steam are all here behind the scenes - purchasing games, chatting with friends, voice chatting with friends, and more. All of the greatness you're used to with Steam is now just readjusted for the big screen.
I found the chat much better on the big screen than I thought it would be - and quite enjoyed the experience in doing so. I'm not much of a gamer on the big screen - being an owner of triple 120Hz 1080p-capable screens - but the chat mode on the big 55-inch TV I have was actually great.
It was clear, and the chat UI is intuitive - I expect nothing less from Valve by now. The chat window sits on the right and takes up one half of the screen, where the left half of the screen is taken up by your friends list. Both at the top and the bottom of the chat window are options like FRIENDS, GROUPS and down the bottom, there's a shortcut to STEAM and to the right of that we have MORE, ACTIONS and START VOICE CHAT.
I'm sure you've noticed by now that I type these as uppercase - because that's how Valve has done it with Big Picture - it really stands out. Especially on the TV when you're sitting a few feet away compared to an arm's length from your monitor.