If that CPU is hitting 70*C under load, you really should look at a better cooling solution. The old Thuderbird cores can take the high temperatures, but the new Palimino cores---like those powering your XP2000+---are not as forgiving. I checked out that cooler, and it's only rated for up to an XP1900+. If I were you, I'd seriously consider purchasing a different cooler, preferrably one with a copper base as these transfer heat much better than aluminum.

But, based on how much you have in there, a better power supply would be a good idea. Antec or Sparkle are what I recommend and happen to use a 350W PSU from both companies.