What type (and brand) of rice are best for making paella?

I'll add my voice to the bomba chorus. But the most important thing is that it must be a short grain rice. Arborio is an adequate substitute but I'd look for the bomba first. Cooking paella is not like making risotto. Once you add the hot stock you don't stir it. What you are trying to achieve is the "socarrat"; that crisp crust at the bottom of the pan.

I agree that bomba (it's a type, not a brand) is the most authentic and good. I don't think that most other Spanish rices work or taste nearly so well, even those that are labeled "paella" rices. So my second choices are the Italian arborio or carnaroli.

Calasparra or La Bomba rice, both from Spain are great. You can easily order them online at latienda.com or pick them up at a local specialty store. They provide just the right amount of risotto-like creaminess to the paella, without the headache of stirring.

A medium grade rice works best. See http://www.finecooking.com/articles/how-to/paella.aspx for specifics.

I use arborio rice. Check the site link for inspiration at http://www.food52.com/recipe/paella