Don't know about name brands, but fast (3Ghz+) multi-processor (go to Intel site to spec. this), fast bus, fast ram (as much as machine can handle), fast hard drives (at least 2 on the bus), big power supply, big box, and big fan. Unless you use rendering software that supports programing on the graphic adapter chip, graphic adapters do not affect rendering. Many medium to high end adapters work OK. If you are a Sketchup user, you have to carefully research compatibility. While it doesn't affect rendering a 24-30 inch display is good. Among other things, highest screen dpi is best.
You should research the hardware reviews, it stands to reason that any single person here will know less then the testers.