pc133 any crucial, mushkin, micron (dont nkow if they are what you would consider cheap, but they are good overclockers)
ddr would be samsung pc2700 on samsung pcb (if its 3rd party pcb it will oc but not as well, also look for ctl chip, sometimes you can find some and those were better ocers that dtl), mushkin again, corsair (but not cheap), micron, crucial
another brand i have seen in europe is apacer i think its called (havnt heard much of it in north america, but somebody was asking before if its any good and from the couple sites i read it seemed to be ram of choice in europe/asia apart from popular north american brands)