The dv4 and dv6 both support: 2.3GHz i7-3610QM processors, GeForce GT630M graphics, Beats Audio and 14-inch or 15.6-inch (1366 x 768) displays respectively.
The dv7 model is little better with: 2.6GHZ i7-3720QM chip, GeForce GT 650M graphics and 17.3-inches of 1920 x 1080 screen. The g series comes with weaker processors, varying from i3-2350M to i5-2450M Sandy Bridge variants and a 14-inch screen.
The g series will be cheapest and will cost you $630, while the dv6 and dv7 around $940. It's speculated that this models will come out in April. I'm saving my money for the dv7 model, it looks amazing! But, till they get on the market, check out the promotional videos: