To be honest all of your choices would be over kill if you at your max resolution. A single 4870 would suit you fine for now, or step up to the 4890 if you are looking for longevity. Also, I'd recommend looking into the xfx ati cards as opposed to sapphire or Asus as it's generally accepted that their warranty, and rma procedures are superior.
As far as heat issues with ati cards, personally I've never had an issue, but my case is well cooled, and ventilated. I haven't overclocked my 4870 at all, and I let Catalyst control the fan speed, and it's been great since day one. It's played everything new so far without any issues at 1920 x 1080.
Oh, and welcome to HWC! The above is just my opinion, and i'm sure others will chime in with tons more to aid in your confusion.