Now that I look closely at the Dell, I see that it's 8600GT uses slower DDR2 memory where as the G1's uses DDR3. I think that combined with the faster CPU wins the G1 my vote. You just have to decide if you want a 17'' or 15'' screen.
I'd go for the 15". It's a perfect match for a 15" laptop. Of course the 1720 may have better cooling for overclocking because of its 17" chassis. overclocking the GPU on the 1720 is a breeze. I gained 1000 points in 3Dmark06 via overclocking with only a 4c temp gain.
Yeah ASUS is better it has a better CPU and GPU otherthan than it has few more extra features like esata which can be handy.I suppose dell gives only 1 year warranty If so ASUS warranty plan is great with Accidental Damage Warranty
A Dell XPS M1530, with a 8600GT, 160GB HDD with 7200RPM, and a Intel® Core%u2122 2 Duo T7250 (2MB cache/2.0GHz/800Mhz FSB) processor. The XPS costs the most, but I don't mind spending an extra $200 bucks.
It costs the most, but also looks the best IMO. I've seen the new Inspirons first hand and they're better looking than they used to be, but still not great. Asus' are pretty sleek, but I think the XPS matches it or passes it.
Keep in mind though, you may have to wait a while to get it since it's new to the Dell line up.