urgent server selection for a project

hi gurus,

iam new to this area, my managment has given me the work to look/buy for a server machine.
i would like to know the requirements for selecting a server. i need to buy a server in which windows 2000 is os, oracle 8iserver, java server, asp with suitable virus software.
This is for a cleint company where they deal with water proffing solution business, work for 12hrs to 14 hrs a day and data is important as they have daily sales and customers data.
shall i go for a raid 1 or 5 with 2 cpu system.

thanks
ajay