The only things I still keep local on my drive:
music my family pictures my email, contacts and calendar work files
If you imagine a tablet/netbook with GoogleOS, I'm still scared to death of losing the network. There is some talk of offline storage, but the details are super-fuzzy.
On a plane: where is my music or my videos? At my grandparents' place, where Interent is still not quite reliable In the middle of visiting Death Valley