The Everio G series standard-definition models for 2009--the GZ-MG630, the MG670, and the MG680--have incorporated a higher-resolution 800,000-pixel CCD, up from the 680,000-pixel versions in previous models, but the sensor is the same 1/6-inch size. What effect that'll have on low-light quality, never one of JVC's strong suits, remains to be seen. The models also have 40x "dynamic zoom" lenses, a kind of fudgy cross between digital and optical zoom (it uses "nearly all of the CCD's effective pixels") like Canon's Advanced Zoom, that I suspect is based off the 35x lenses of the previous models.
In a somewhat interesting twist, the MG680 and MG670 can perform HD upconversion in-camera when outputting via their mini HDMI connections to an HDTV. In theory, this should deliver better quality than allowing the TV to do the conversion. Generally, showing SD video on an HDTV will look pretty bad no matter what you do, but the HDMI signal alone is better than composite. We'll have to check that out.
The GZ-MG630 (60GB; $429.95) and MG670 (80GB; $479.95) are slated to ship this month; the lower-end model will be available in silver, red, and blue. The $549.95 GZ-MG680 has a 120GB hard disk and will ship in February.