Word on the street is Dell will release a new Inspiron 910 sub-notebook (I prefer the term 'laptot') on August 22 shipping with Ubuntu Linux. Further leakage from Gizmodo says that the machine will be $299.
I've written in the past about howon the desktop. There is no need to run Windows (or MacOS for that matter) when you are using the machine primarily for browser-based applications.
I've been running Ubuntu on a Thinkpad X300 for the last 2 weeks and while it's still a bit too geeky, the issues I have run into appear to be largely due to the fact that IBM doesn't officially support Ubuntu (yet.) With the exception of Adobe Photoshop I have yet to run into any business reason why I can't use Ubuntu full-time.
In light of consumer response to Vista (not great if you haven't been paying attention) there is an opening for Linux to swoop in and grab some market share. The big hardware vendors just need to start playing along.