IMO, with the price of RAM today, there's never a real good excuse not to use ECC memory. Many crashes are really just temporary RAM errors, which you don't see with ECC. If you do have a major problem with RAM using ECC, instead of a mystery crash, you get a clear indication of what happened, a memory error! I've been using ECC ever since the original Pentium chipsets started supporting it, and standard parity before that.
As far as the type of RAM to get, you obviously want to match it up to the requirements of the MB and processor...
As far as the type of RAM to get, you obviously want to match it up to the requirements of the MB and processor...