I would settle for an ugly case (just a box, nothing fancy, $18 at Microcenter) and spend a little more for a bigger processor. Other than that, you should be good!
For example, I have 2 computers, same OS, one is 2.4g processor and 2g RAM... The other is 3.6g processor and 1g RAM... The 3.6g processor works much better with CAD/CAM for very comlicated drawings and generating complicated tool paths. Just my experience.