I would choose a Gigabyte or Asus G41 chipset mobo and E5300. Preferebly giga EG41, since it is touted to be energy efficient. Intel's 2D graphics handling is quite satisfactory and that is important from coreldraw point of view.
No Mate !
An 8600 GT requires only 18 watts at idle, So no problem going for 24/7 if the OP does not mind an additional 20 watts power consumption from the rig.