I think the best would depend upon how much voltage you are going to run through the memory and how high a FSB you want to aim for and then the rest of the answer comes into the matter of price.
I personally like Kingmax as it appears to run well without massive voltages. Crucial DDR is good and handles higher voltages with ease.
I've ran everything but the kingmax stuff.. Corsair is awesome for data integrity for fsb under 150... But for awesome o/c's and data integrity try using some Mushkin Cool pc2700 I got evryone of my seti boxes running this 24/7 @ 175+ fsb, turbo settings, with the fastest ram timings without even a hiccup.. Purely the best ram I have ever bought.. Stay away from crucial.. I have had lots of bad o/c's from them.. they only tend to o/c to 146-148 tops...
Hope this helps..
There is no way pc2100 crucial can run 200/400mhz fsb speeds I've owned 6 sticks of this ram and the most I have gotten from any of them was 152 with relaxed ram settings.. and 2.9volts.. Only people I have seen run over 200 fsb has been people using pc2700 or higher..