I just landed a freelance video editing gig and need to buy myself a new Mac Pro. The main programs I will be running are Final Cut Studio and After Effects (with a fair amount of rendering). I'd like it to last me 3-4 years and I'm willing to spend up to $3,500. Should I buy new? refurbished? Ebay? 4,1 or 5,1 ? Can I save money buying crucial RAM separately? At my other job we have an early 2009 2 x 2.66 GHz Quad-Core Intel Xeon with 8gb RAM. This computer runs Media Composer and After Effects smoothly, to my enjoyment, but I'd love to be ready for 2K or even 4k editing and possibly 3D animation. I start the job next week! Help!