What SD card for really good Ready boost speeds?

Ok, im getting a new laptop and Im going max out the ram first, but I also want to put in a SD card in the laptops internal card reader so I will allways have ready boost on it. I would like to have 2-4 GB of ready boost. Im just wondering what I should be looking for and what type of speeds I sould try to get? Thanks alot!!

I cant even tell im using ready boost on my desktop.

True, but I figured it cant hurt performance.

sandisk Extreme III or Lexar 133x.