AmesMUG: Macbook Pro Internal Hard Drive

[Clark Colby]

So i was originally planning on buying a new external hard drive but  
i think i have changed my mind to buying an internal. I was looking  
at the Apple store but it seems like they are over priced. I then  
started shopping online and found a Hitachi 200 GB 7200rpm Sata Hard  
Drive. http://www.zipzoomfly.com/jsp/ProductDetail.jsp? 
ProductCode=10005818&prodlist=pricegrabber it is $187 here and $204  
at NewEgg.
It really scares me to think about losing all of my documents and  
programs on my current hard drive and would really appreciate some  
help with the switch.
My first question is if the hard drive i am looking at is a good one?
Secondly does it void the macbooks warranty to add a new hard drive?
Third where to i store all the programs or information during the  
change? I have an external hard drive but it is full as well..... I  
am hoping when i take out this 80GB internal i can buy a case for it.
So my last question is what is a good small case not to expensive for  
the old internal hard drive?

Thank you,
Clark Colby