At idle, you shouldn't have a temp higher than 45 at a maximum, if you ask me.
If you have that many fans, you need to make sure they are going to right way. The general idea if to have a 1:1 input/output ratio for the fans. Simplty put, you need to have the same amount of air being sucked into one side of the case as you have being ejected out the other side. The general idea is to have all the fans on the front and one side (or top, depending) bringing air in, and the rear panel and other side being the exhaust.
Having the silicon of two different cards isn't as huge a problem as some might lead you to believe, but it can slightly hinder cooling ability.
Also, if you have that many fans, you obviously don't mind the whole "My rig sounds like an airliner when it spins up!" bit. If you have the ports for it, invest in 120mm fans, replacing your 80mm's. They move roughly twice as much air.
If these aren't helping your heat problem, look into adhesive heatsinks for your RAM and GPU. Though they are not as incredibly effective as some might want you to believe, they do give the chipsets more surface area for heat to dissipate.