Accessible SF

I've read in quick succession recently two novels by an up and coming SF writer named John Scalzi. I've been reading his blog and he brought up an entry he made a while back concerning entry level SF. Specifically, SF for people that don't read science fiction.

Personally I have always found good science fiction to be entry level science fiction. Every new science fiction (or fantasy) novel has to introduce readers to a new universe and a good writer should be able to do that for a long time SF reader and someone that has never picked up a SF book before. I think Cormac McCarthy's "The Road," Roth's "The Plot Against America" and Atwood's "The Handmaid's Tale" all straddle that line nicely.