Unfortunately there isn't a whole lot of ways to cool an athlon system without a little noise... But you can. One option is to use packing foam on the sides and everywhere else to insulate the noise, another option is to install some real professional stuff that won't increase your heat such as
Sound Deadening Material. On top of that, you can get a REALLY nice heatsink like an SK6 or Gladiator, then stick Panaflo fans in the case rather than any other brand on account of their liquid bearings that make their operational decibal level quite low.
On the heat side of things, it depends on where you live. For instance some people might have higher temps for their idle / full load's but then you ask what temp it is for their room or whereever the computer is being kept and the temp in that area is higher, so the environment is a big issue as well. I usually try to keep the ambient temperature below 80 degrees, if I can, 75 or so. Another thing to take consideration of is that the temps you see on an A7X series of boards is that Asus modifies the bios for stability, but unfortunately it results in higher temperatures on most boards made by them.
Hope this helps a little.