I would choose for a 15" MBP over the 17" - the new LED backlit screens are noticeably superior to the old style (which the 17" is stuck with, currently) and the 15" is easier to carry. If you need more screen real estate, you can always dock it into a bigger monitor at home.
Haven't owned anything but Macs since 2000ish and couldn't turn back at this point, even when the company frustrates me (no desktop aside from the Mac Pro or the iMac, ridiculous upsell charges for components, etc.).