I've been using a chromebook at home as a mostly-primary computer, replacement for a 13" MBP w/ SSD (which cost ~$2000 when it was new).
The only thing that's weird is printing, but for 90% of "generic internet stuff" it works fantastic. ChromeOS just updated last night and I haven't even had a chance to mess with it.
It will even work mostly-ish as a web-dev terminal as it'll do SSH as well as chrome developer tools (although it is slightly hokey).
I'm a 15+ year linux user and I don't mind using the chromebook at all AS AN ADJUNCT TO A REAL COMPUTER!
A ChromeBook is ~1/10th the cost of a "real" computer, is SSD by default (only I think), is great for "kitchen computing", great for travel (just turn on password-protection and it gets very good battery life, and you don't mind if it gets lost, stolen, or damaged and it's very lightweight).
It's got a lot of advantages even for a power-user, although it doesn't (yet) replace a "real" computer / linux / osx box.
The things I've used my "real" computer for since then have been seashore (gimp), inkscape, video editing, printing, and some minor gaming, and I've had the MBP for 1-2 years and the chromebook for ~6 mo.