<< ECC RAM isn't very effective at error correction anyway. It can only possibly fix 2bits out of a 32bit string of data at this point. So for that, it's not worth it.... >>
It can actually only fix 1 bit out of 64-bit. But this isn't a problem because memory errors are typically very rare, and the 64-bits of a typical memory line are scattered all over the place so it is fairly unlikely that you will have a multiple memory errors. Besides, I don't see your point. Surely the ability to correct 1 error, and detect 2 errors is better than not having capability to do this at all.
<< ECC RAM is slower, because like the guy above you said, it has to check the data as it is being processed. >>
It is only slower in the case of a read-after-modified-write where a memory location is read immediately after it has been written. In the case of a typical read, ECC is checked while the data is actually being used, and in the case of a typical write, ECC is written after the data has been written to memory. Since a read-after-modified-write is fairly rare, the performance penalty is pretty low. It is typically 2-3% slower than typical memory and in some cases, the performance is identical. 2-3% is within the margin of error on several benchmarks.
<< ECC RAM is not very overclockable, if overclockable at all. If you want to overclock your RAM (it's a very cool/good thing to do), you should buy regular unbuffered, non-ECC memory. >>
Why would this be the case? The memory chips are the same, all that is added in is the ECC checking lofic which is checking for errors. Since this isn't typically a speed path, there is no reason why this logic should create issues when overclocking. In fact, if you are overclocking ECC's ability to check for memory errors may prevent system instability.
<< ECC RAM is also a tad more bit expensive, ecpsecially with the rising prices of memory. >>
It is approximately 10% more at most reputable memory dealers. For 256MB PC2100 this adds up to about $3-4 more even with the recent memory increases.
<< In fact the only thing I can see ECC ram for is if its ECC/Registered where you need it for motherboards with a fourth slot for memory >>
ECC is useful for data integrity. If your data is important to you, or your system uptime is essential then ECC is very important. Servers, workstations, and home computers that contain important data should all use ECC. If it saves you from disaster just once during the life of the computer, then it has more than paid for itself.