Best tablet + keyboard for Writing essays/articles

Hello,

So I'm selling my Nexus 10 and looking to upgrade to a tablet plus keyboard combo that will make it easy to write essays/articles. That's the main thing I want it for. I will be watching few videos/Skype and web browsing but that's basically it. Any size is fine but preferably 8 inches or more.

Budget: maximum of $500.

Any suggestions?

Thanks,
Crazysah