It might depend on a number of things - your location, your budget and your requirements.
Windows 7/Vista/XP, VS2010, VS2008, SQL Server 2005, Oracle 9i, My SQL 5.0, Crystal Report...
You are looking at 3-4 GB RAM requirements here.
Anything less than that would not be optimal.
Hard disk - at least 250GB - anything more than that is a bonus.
Your choice of brand would come in only after you decide your budget and specs and then do some more analysis on these various brands.