i wasnt planning on overclocking, well not to start with anyway, so i will just use the one that comes with it i guess. Unless its looks really crap and spoils the look of my computer
Just monitor the temperatures for the first few weeks that you own the CPU, if things get a little too hot, then replace the heatsink and fan, but if temperatures stay fairly reasonable, I see no point to making any changes.
Actually the LGA775 or Prescott fan is rated up to 4700 RPM. It is the best air cooler for the LGA775 processos including the 560 whose "heat can kill". I've oced my 520 to 3.73 GHz and my temps still stay 10C degrees below dangerous and my stock hsf is hummin' (not more like screaming) at 3900 RPM.
Not sure whether this is a joke or not, but I'm should probably warn you that even though AMD will probably replace an overheated CPU, they probably won't bother replacing any other equipment that could be damaged due to overheating.
You should never willingly allow a CPU to run at dangerous temperatures, regardless of warranty.