Apple Logic Pro /LogicExpress Discussion

Can anyone recommend good RAM to bulk up my Mac Pro?

I've got the 2x2gHz with Dual-Core Intel Xeon, with 2 sticks of 512mb  
DDR2 FB-DIMM, and want to double the RAM.

In the past I bought from OWC, but twice now I've had to return the  
RAM because of kernal errors, so am looking for an alternative that  
works on my computer but fits my dirt-poor budget.

Thanks,

Gregory