This is the board temp and is a bit high. My ambient is a nice cool 20 C (I'm in a basement) and in my case with an 80mm intake and 120mm exhaust, an Athlon 64 X2 4200+ running at 100% and two HDDs, my Tcase is about 31-32 C. My temps do NOT drop much once I pull the sides off- in fact, not that much inside feels warm at all. Not cold, but not even body temp. I bet that you need to clean up those wires and make sure that the fans are drawing air in at the bottom front and out the top back. I'd forget the side ones as I have one and it actually makes it warmer for the CPU and board temp sensor as it recirculates warm air for the most part.
My CPU runs at a full-load temp of about 42 C and idles (1 GHz) at 25 C with 2200 rpm on the heatsink fan. Yours should be somewhere in that range, although the idle might be more like 30 C since the Core 2 won't clock down quite as far as the Athlon 64s do and AMD's stock heatsink is better than Intel's. Your E6300 puts out less heat than my chip, so I'd expect your full-load temp CPU to be around 40-45 if your case is well-ventilated and your Tcase to be around 30, maybe a few degrees C higher.