ive bought multiple refurbs off woot (roku, my TV and something else cant remember what) and have never had an issue. you can look up what the common refurb is on that model and if it is something dumb then go for it.
I am running an AMD right now in my desktop . cannot wait until i get an ivybridge I7 in there in the near future. i might as well just build a completely new machine since i will need pretty much all new components to run an i7