Plain white rice is the cheap white rice you get in the supermarket.
Spend a few milliseconds on the web, and you'll see beaucoup reassurances that slow cookers are GREAT for making rice. I "get" slow cookers, and use them for a lot of things, but I never tried making rice with them. Contrary to these reassurances, I am not impressed. Nobody said it was "better" with a slow cooker, but there are a lot of conveniences in using one.
The 2:1 is the standard water:rice ratio for just about any rice I've ever heard of.