Im going to try a 10k from OE to 5V and see if that works, ill report back!
Btw, i wrote a piece of code in the void setup to put all latches to low and shift out B00000 (each zero is a LED in off state) to all shift registers
So I tryed it on a single shift register but no luck, its still flashing when getting powered up. However when I put a 10k resistor on the latch to ground on a single shift register on my breadboard it won't flash at all, but on my cube with 6 registers it will flash when using a 10k pull down resistor.
Well, 10K is only 0.5mA of pulldown - you could go stronger, like 1K for 5mA of pulldown. Arduino will drive it high okay.
So I tried 1k, still some very faint flashes on powering up 
Got it fixed, I was so stupid to shift out B00001 instead of B00000 at the void setup(I shift out B00000 to clear out all the shift registers). So I got it fixed :)!
Cool.
Ok...Another question. For now I have my Master Reset/Reclear tied to 5v. However I want to control the MR.
Now is it right when I pull the MR to LOW that all the shift registers will be cleared, and the bytes that were in the shift registers are gone(even when I set it to HIGH again)?
Ok, pull MR high with 10K resistor, have your sketch pull it low when you want to clear the input register.
Outputs will go low on the next rising edge of the output register clock; See the final RCLK on the diagram on page 4.
74hc595_TI.pdf (915 KB)
Thanks! Thats exactly what I was looking for. This is faster and easier then writing 0's to the shift registers.