Yes, vista is Spanish, and it means a view. It usually refers to a scenic view, such as a mountain, or a snowy field.
I'm not certain, but I believe Windows Vista was named as such, because of the huge overhaul in it's GUI. In my opinion, the new Vista GUI looks much better then the old one, and this was most certainly what Microsoft had in mind.
So...why did they name it Vista. I mean, I knew what a Vista was before Windows named their new OS that, but I still think that Longhorn was a badass name even though it was just a code name...sadface.