Beste small Windows 8.1 tablet + attachable keyboard Combo

For college, I'm looking for a small device that allows me to do some Office work but also a device that is suitable for reading. That means my options are:

- Laptop + e-reader

- Hybrids/convertables

- Tablet + attachable keyboard

The first option is probably not the approach to take since I'd be doing a lot of annotating, highlighting etc. and I don't know an e-reader that does that as well as a device that runs Windows. Secondly, I'd be doing a LOT of document transferring from laptop to e-reader which will probably become a pain in the arse.

I'm not entirely sure where the distinction lies between hybrids and tablets + keyboards, but one thing I know is that the tablet part of it should be small, light, well-build and and have an excellent screen that handles sunlight very well. Almost as important, the keyboard/touchpad should be solid.

I know I'm being pretty vague as far is size as concerns, but I don't want to exclude too many devices for consideration. Let's just say it should be large enough to comfortably use Office.