my 8800gt still going strong and handles any game I have thrown at it.
I can understand you saying games look better with the new card as I assume the games are either dx10 or 11 otherwise a dx9 game wont look better just because a newer card, also dont understand how windows desktop can look better.
my view on the heat is graphics cards do run too hot and use too much electric but that is a problem on older cards as well, my 8800gt is 70C on the windows desktop.
looking at your gpuz stats I see my 8800gt on stats is showing its age now
you have triple pixel fillrate, triple memory bandwidth, triple memory size, the only thing close is texture fillrate I am just 25% less on that one. But as long as I dont notice problems in the apps/games I run I am happy with my 8800gt.