Best thing to use on White is a can of black paint. Joking aside whatever you use it will always look clean, that's just the nature of white. You could go economical or ease of use type products, or even both if you want. I'd go with something durable personally like Zaino, Twins or Collinite. It's all going to look about the same, so why not go with a sealant that repels dust a little better than a nuba? How do you like your car?
I'd highly recommend Poli-Seal topped with Aquawax. I use that combo on a white BMW 650i that I maintain weekly - and it's the car I show to prospective customers in order to lure them in.
