On my new machine (2.2GHZ i7), I had the 750Gb 54K drive and the glossy. I upgraded the 750GB drive to a 640GB 7200 Samsung drive. I don't really notice a battery life decrease, but again I had an Early 08" MBP that didn't last that long.
I also got rid of the glossy screen and got the Matte screen, and love it. I am used to it as that is what was on my old machine.