Best hardware for creation of complex vector graphics

I am creating extremely complex vector images in Corel Draw. It involves lots of complex objects , many transparencies and extrusions and fountain fills- you name it. My old rig is struggling so am interested in upgrading. I am looking at what the key component to enable near instant redraw of complex vector graphics may be. Should I look at my budgetry bias going to the CPU or the GPU for instance. I understand these types of graphic applications are like a database so I would guess that CPU/RAM is very important and not so much a high end graphics card. Therefore I am going for a Core i7 but which is the best bang for buck at present? There is a huge jump from say the latest 860. Are the higher end ones worth the extra? Also what graphics card to match it up.