I think you haven't completely understood the comments/answers till now, it is understandable since you state you're new to the Mac world.
From an aesthetical point of view the 15" had been the same, if I'm not mistaking, since 2006(the switch to Intel) till October 08. It used to have a silver bezel and silver keys. October 08, all of Apple's portables were updated, the 13" and the 15" got the unibody structure and the black bezel,black keys that resembled the one of earlier Macbooks and Airs. The 17" stayed the same for a few months longer, till last Tuesday.
The 17" is supposed to stay this way for a few years, especially given the Matte option. If the battery solution stands in the way of selling more laptops, this could change, but I doubt it.
The pros, however, get updated from an internal hardware point of view, every 8 or so months. It also depends on Intel's roadmap. Mobile quad-core Nehalems (from what I recall) are supposed to be be assembled in this year's last Quarter or 2010's 1st Quarter. This will be a huge deal. The 17" Pro already got the .133 GHz speed bump the other portables are expecting, same would go for the iMac and more of a bump for the Mac Mini, but I could be wrong here (..as for the rest of the post). In my opinion, other than a graphics card, and I have no idea what NVidia or others are up to, the 17" could actually stay the same till quad-cores are available. I'd suggest keeping the current "new" portable for a year longer, or if anxiously wanting to jump on the Mac wagon, buy a 15" if not too small or the current 17", selling your current PC, and selling that Mac if necessary next year, if the processor upgrade is needed.