Im not going to do an indepth spec for you, as there are people on here better than me at it. However for rendering, the main thing you want to look at is the CPU. What rendering program you using? If its a program that supprts bucket rendering such as final render or mentalray, then dual core is the way to go, as it will render literally twice as fast as single core. For real time 3d modelling etc, ram is also quite important so the more the merrier. The GPU however is less important, but if you want it for games then maybe get a decent one. Just don't go and waste loads of money on a top end GPU expecting to see a great boost in rendering. a decent harddrive is also usefull if your going to render uncompressed frames, as ive had projects with 2mb a frame and upwards. So overall I recon your lookig at a high end Conroe system with 2-4Gb ram, mid range GPU, 1 OS harddrive and 1 storage harddrive.