Im considering the perspective that you wish to do free-lance work on your computer as well as gaming. So taking that into consideration you may be better suited to a home-built machine than a pre-built one as your needs may differ from those of the high end computer gamers who buy machines in your price range.
One professional looking computer case which is quiet, solidly built and comes with a locking mechanism for the front drive bays which will keep your most important asset, your I.P safer from being spirited away. It also helps you with presentation if you intend to bring clients into your home to show off the work.
Important consideration, time = money:
Raid and the humble solid state drive may very well be some of your better companions. Data security (Again its the I.P principle), performance and simplicity are perhaps some of the orders of the day here.
With a Raid 1 array of 2 * 1 TB drives you can be sure that if one of your HDDs go down you will not lose hours, days or even a weeks worth of data. Furthermore since you seem to be working with some large files the higher read speed coupled with the extremely high RAM quantities you demand will keep the pipes better fed.
With a SSD you get all the benifits of a Raid 0 array for your primary system drive with far better reliability and ease of setup and maintenence. Obviously some are designed as system drives and some are not, however since you'll be looking at the middle of the range options it won't be a problem.
Tease.
