I'll add my own input here. Mattup, from my experience, you are wrong. I have had the following: 3200+ Winnie, 3800+ Venice, 3700+San Diego, X2 4400+.
Now for comparison purposes, I has my SD @ 2750mhz with 1.65V (yes, 1.65V) which loaded about 49C on an XP90 (Al not Cu) with a 92MM YStech fan. When I used this on my X2, the idle temps were the same, and the load temps about 7C hotter. This X2 was at 2600mhz with 1.49v.
Thus, the temp is not abnormally high for such a high clocked CPU, BUT it does seem high for the voltage. Either put a more powerful fan on there (doesn't have to be a vacuum, just something that will actually shift air e.g. panaflo 120x38mm on a fan controller, or any 38mm deep 120mm fan I suggest, running at about 5v).
I think temps could be a bit better, 10C over say james.miller's single core is a bit high, but I would say 4-7C higher is about where it should be. To me, it sounds like poor airflow in the case though.
From my experience: I built my sister a P4 3.4Ghz Prescott. I gave her my XP90 and fan when I put my water in. Her P4 was idling 60C and loading about 80C (not clocked) - yes, very hot. I put in one small 80mm fan 2000rpm, quite quiet and idle dropped to 45 and load 65C. Moral, case flow might be something to check as well as heatsink/TIM application.