the 5xx series is know to have extreme heating issues. My buddy has a gateway with a 550, it idels at the same temp. Im not sure about a bad batch (altough i guess it could happn) rather the whole prescott core is hot. Getting a better heatsink would help alot, but as long as you do not expirence actual problems while using thew PC i wouldnt loose sleep over it.
I read the comments on Newegg also. I have a 550 3.4 Prescott on the way from there. But I also ordered a $25 Ultra heatsink/CPU fan for it from Tigerdirect. With 3 80mm and a 120mm fan in the case (along with 2 hard drive coolers) I hope I don't suffer from too much heat. Should be up and running after next weekend so I'll report back if this thread hangs around.
By the way, I ordered the CPU on Thursday @ $270.00...happened to check back on Friday to read a spec on it and the price had gone up to $314!! Glad I ordered on Thursday!