CPUs and GPUs are technically designed to run constantly at high temps for prolonged periods of time.
Both of them being constantly at 80C isnt bad, they're just being used a lot.
The real problem is cooling. You dont want them to get too hot, and preferably the lower the temp the better.
And today a lot of electronics companies have gone to cheaper solder which doesnt hold up at high temps as much as the more expensive solder can. This is why we get the YLOD on PS3s and RROD on Xbox and why reflowing "fixes" the problem.
Of course reflowing isnt a fix, but finding better ways to cool the device is.
I recently saw a post about reballing, seems pretty time consuming and complex for some, but looks like if you can do it yourself then that is the best option.
Not installed the latest mmCM, or play much on my PS3 so not sure what temps mine runs at...