If I were you I would wait, Sandy is supposed to bring better power effiency, better performance, and cooler chips. Which should replace the chips in the G73 leaving it at the same price, but with better performance. Theres also the chance of better gpu's also.
My guess would be that since its launching in Jan. we should see the chips implemented by feb. or march since asus is a pretty fast at adapting new parts.
I've been waitng a year for this lappy. My dream machine is the G73 with sandybridge + 580m + optimus = BA gaming laptop, with 3-4 hour hours of regular use, that will last me through college and it appears that the next refresh of the G73 should bring it.