I am in no way affiliated with the following plug:
Buy Kingston Ram! This is not an advertisment just a suggestion, just a quick note everyone might like to know:
Kingston has 2 majorly differnt types of ram, Their normal Kingston Ram, and Kingston Value Ram.
What makes kingston better than most is they press their chips with the first 10% of the ink, then make value ram with the other 90%.. Most companies use the majority of it on all the ram, which is why normal kingston ram has a 99.9% perfection rate......
Dual CPU system require the RAM to be registered as well (at least for DDR systems). I'm not 100% sure on whether it needs to be ECC for a dual CPU system, though.
Our real world experience doesn't show any major benefit to ECC unless you need 100% uptime, though I'm not sure if ECC would prevent a RAM failure related crash or not.
We've only had one RAM failure related crash in 4 years of doing hosting and more than 70 servers. We always use Micron RAM if we have a choice (crucial.com). We're also very careful to avoid static discharge around our equipment and when installing upgrades.