Well...there are a couple of things to keep in mind about the Surface 2. First, apparently, the Surface 2 has been optimized for playing videos - note - playing videos - not streaming videos. This means, you either have the videos on the internal drive or on the SD card. According to MS, if you do this, you should get about 10 hours of battery life. I have never tried this, so, can't comment. Second, I am not so sure the Surface 2 has been optimized for web activities - browsing, streaming etc. Strange, I know, but there it is. I have a reason for making this assertion. Take a look at the two links below. The first one is about the Surface 2 and the second is about the Surface Pro 3 (yes, the one that is going to be released on June 20th).
Surface 2:
Surface 2- The 10 inch tablet with Office (Look under battery life - it clearly says: "Up to 10 hours video playback"
Surface Pro 3:
Surface Pro 3 - The tablet that can replace your laptop. (Again look under battery life - it clearly says: "Up to 9 hours of web browsing"
Notice the difference? From this I conclude that the Surface 2 is not really web-optimized, while counter-intuitively, the Surface Pro 3 is (I am not complaining, I am intending to buy one as soon as the device hits the store shelves!).
That said, I currently use the Surface 2 (RT) for the following purposes: (1) Office (primarily Word and Powerpoint); (2) Mail, Calendar (I use the Modern UI App not Outlook) with 2 accounts checking mail as it arrives and with notifications on; (3) Browsing (I most often use the Modern UI version of IE) - usually, I have about 3 tabs open when I am browsing - the sites I frequent have a lot of flash content etc.; (4) Flipboard - occasionally; (5) Bing Recipes - very occasionally; (6) Weather app - this is always on; (7) Plex - occasionally; I also use a few other apps like Currency Converter, Here/ Bing Maps, Calculator etc. from time to time. But I do remember to fully close them - by dragging the app window down and waiting for it to flip over - when I finish with them. Brightness is at about 40% with Adaptive Lighting enabled. Camera is off, BT is off, WIFI is on when I am using it or when I am at work or at home. In transit, if I remember, I put it on flight mode though I should mention that I usually also have the tethering facility on my phone on and when there are gaps in my WIFI coverage (for example if I am moving around) then the device is connected to my phone.
With this profile, in about 8 hours, I find the battery level dropping down to somewhere between 35-40%. I have noticed that the days when I am doing a lot of web-centric work, the battery levels are lower, which kind of confirms my speculation as mentioned above.
Again, I think MS should have optimized the Surface 2 for web browsing/ web-related stuff, but there you have it!