This is entirely dependent on the year of the MacBook. The new 13" MacBook Pro Retina keyboard is not the same as the regular 13" MacBook Pro. You also wouldn't be able to interchange a keyboard from the older 13" MacBook models (white MacBooks) with a recent 13" model.
A keyboard for a Macbook pro will often cost around 100 dollars. This will vary according to possible discounts and coupons you receive or have. A second hand keyboard will cost around 50-60 dollars.
September 2012
I hope so!
The MacBook Pro currently (November 19, 2012) comes with OSX 10.8.2 "Mountain Lion." Earlier MBPs had earlier systems.
The MacBook Pro is available with faster processors, includes FireWire and Thunderbolt connections, a SD card socket, has an illuminated keyboard etc. These are not available with the MacBook.
MacBook Pro does not come with eSATA support. If you have MacBook Pro with ExpressCard support, you can get adapter which would allow you to use eSATA. Note: Latest MacBook Pro laptops do not come even with ExpressCard support. Firewire is the fastest available option right now (2010).
1000 pounds
MacBook Pro is the best you can get
If you're referring to the MacBook Pro's optical drive, those made mid-2012 or earlier and are non-Retina reside hidden either in the front or the side. MacBook Pro Retina versions don't have an optical drive.
MacBook Pro!
The macbook pro!