Convince me to get a Chromebook/Android tablet

I need a new laptop.

Naturally, the first choice for me would be an Ultrabook (see my previous posts) or a MBA. However, I've been rethinking my choices.

I know dozens of people who own Ultrabooks or MacBooks but the main thing they use their laptop for is browsing the internet apart from gaming. Since I am not an avid gamer, I feel like that I would be better off saving my money on a Chromebook. The device will replace the 2008 iMac I'm currently using.

I do some video and photo editing, but my family has a Surface Pro which I can borrow for those purposes.

But, are Chromebooks worth it? Or am I better off getting the Asus T100 (Bay Trail tablets), Android tablets or even an Ultrabook.

Prime corncerns are Battery Life, Design & Build Quality, Lightness and Thinness, Good performance and boot up times and good screen (preferably >13 inch)

Also, which Chromebooks would you recommend:

The HP Chromebook 14, The Samsung Series 3 Chromebook (I think the new Acer will be poorly built like the C7). Or should I wait for the rumored cheap variant of the Pixel?

I already own an Android phone (Xiaomi Mi2S), so I don't really want to spend that much on a tablet. (I'll try to install Ubuntu on it to make it more of a laptop replacement.) Which do you think is better? The Nexus 7 , Asus Transformer Pad Infinity, HP Slatebook x2, Toshiba Encore. Or should I wait for the new Nexus 10.

OR alternatively, I could buy a Casetop and slot my phone into it, or wait for the Padfone Infinity (hopefully it will have a keyboard dock and genuinely offer all day battery life. Even better if they made one with Bay Trail and dual booted Android+Windows)

Thanks a lot! Fire away.