All machines come with 4GB of RAM, and while hard drives are standard (320GB and 500GB in the higher end), you're free to add a 512GB SSD to your machine if you so choose, for a mere $1,300. Interestingly only the 15-incher is getting that top Core i7 chip, with the sole 17-inch model is consigned to the 2.53GHz Core i5 (though you can choose Core i7 in the build to order options). Prices range from $1,799 on the 15 (up from the last-gen's $1,699 base price!) to $2,299 on the 17, with a $1,199 starting price on the 13. On the 15-inch you can pick between a 1440 x 900 "glossy" display, a 1680 x 1050 glossy display for $100 more, and an anti-glare hi-res display for another $50 on top of that (you 17-inch users are stuck with 1920 x 1200 and glossy). The biggest tweak outside of these beefy internals is "inertial scrolling" support for the trackpads, à la iPhone, though we're not sure why this couldn't have been added with just a software update. Everything's up on the Apple Store right now for your perusal, with the bigger models shipping "within 24 hours" and a 2-4 day delay on the 13-inch.
Update: Ars Technica confirms that the autonomous graphics switching is indeed from Apple. The boys in Cupertino wrote their own code in order to extract the longer battery life. Unlike Optimus, Apple's solution powers down the integrated graphics when the discrete GPU is required -- something that happens automatically whenever an application requires advanced graphics frameworks like OpenGL, Core Graphics, or Quartz Composer. Optimus works off a master list of GPU intensive apps that NVIDIA maintains. Yeah, we can definitely see Apple not going for that.