My GPU never goes above 80C and I run the game at 8x AA, and High settings... no ambient/depth of field of course...

My GPU Usage % rarely goes above 60% even in crowded areas...
My CPU used to run about 30-40% usage, but since last couple patches, I rarely go above 20% usage now (I7-980x @4ghz)

I use a single ATI 5970HD running in window mode at 1600x900 resolution. I can run full screen 1920x1200 at same settings with same usage %, but I hit my damn windows key so often it crashes the client, and that sucks so I must play in windowed mode.

I agree with the poster about CPU temps.. and your cards should be made to run at 100%, granted SE needs to optimize this game ALOT, as it should not be using this much GPU/CPU

Just be patient, they make improvements all the time, and make sure you get the latest video drivers constantly, they always make improvements too.