Its all about the Cloud these days. Apple, Google, Amazon: They're all pushing their Cloud services - look how Google push content from Google Movies on the tablet.
As such, I don't think the lack of a external storage port such as USB or Mirco Slot Cards will be a big deal for the majority of potential buyers.
Unless Goggle screw this up (or if Amazon responds with Kindle 2), that Nexus tablet will clean up come Xmas, especially at that price point.