Looks fun, but $329 isn't throw-away money. Given that I don't need another computer, the price just isn't cheap enough to say "yeh, why not:.
I realise Chrome OS is somewhat still a market experiment, but I think it would've gone a lot further at a better price point. For ~$200 I would put one in my living room for checking the web & controlling my home web apps. I see that as the perfect way to get people familiar with it (thinking of it more like a tablet, a limited utility), then once NaCl goes mainstream, you have a who market who's ready to start replacing their other PCs.