what's your purpose of buying a mac?
designing? Video editing? Video making?
If you often do the above tasks, a mac would be for you. If you
are more into for eg: gaming, a mac would not do you any good, but
to hinder you, as there are limited games that run on macs.
The mac book pro is quite different frm the mac book.
First the mac book is a smaller variant of the mac book pro,
with a 13inch screen compared to the mac book pro of a 15-17 inch
screen. having a larger screen would mean it would be less portable
due to it's bulk and weight. 3kg++ for the 17inch mac book
pro vs 2.25+ for the 13 inch mac book. however, having a large
screen has it's perks, you can view stuffs in more detail ect.
The mac book, as heard from it's name, is a lower spec version
of the mac book pro. which means, that it's specifications is
lower. Like for eg: lower capacity hdd, and SHARED graphics.
view the differences here.
http://store.apple.com/sg/browse/home/shop_mac/family/macbook?mco=MTIyMTM
The add ons is for you to choose the specification for your mac
book, like having more ram or a larger hdd. It is not really
necessary to purchase them.
I didnt see anything about rebates, and thus i cant comment.
Sry.