Curious.
The cooler in the centre, is that a fan/heatsink or just a heatsink?
If you want to totally chill you insides, i think (as long as noise levels stay down) you should add the optional front fan to suck cold air in. That way (a bit like my Dell) youll have fresh air being fed to the components, instead of room-temp-like air. But as you said, i think your system is fine. Although, my diagram is far superior to yours
Ill post my temps soon.