If you are looking for a point and shoot that also provides a lot of
great manual features I'd suggest the Olympus Camedia line.  I have the
3000z and it offers the most manual adjustments that I've seen without
getting into the VERY expensive range (aperture, shutter speed, flash
intensity, ...).  And yeah it works fine with linux usb / gphoto2... 
Whatever you get check the gphoto2 supported list.

-Kenny