What kind of control should I use in my RNA interference experiments?

"QIAGEN offers a variety of positive and negative control siRNAs. In addition, any of our functionally validated FlexiTube siRNAs are suitable positive controls for RNA interference (RNAi). Our AllStars Negative Control siRNAs, a randomly designed sequence with no known homology to mammalian genes, is the most thoroughly tested and validated negative control siRNA currently available. We strongly recommend to use our RNAi Human/Mouse Starter Kit, which includes HiPerFect Transfection Reagent, Allstars Negative Control siRNA, a positive control siRNA directed against human and mouse MAPK1 (HS/Mm_MAPK1 Control siRNA), and Allstars Hs Cell Death Control siRNA, a phenotypic control siRNA that allows monitoring gene silencing effects by light microscopy."