They could cut $70 in USA and 100€ in EU, where PS3 is overpriced, this would take US price to $329 and EU to 299€ (VAT included), that's roughly $420 including VAT and $350 without 20% VAT, EU price would be still higher, giving Sony an higher margin right here where it sells more.
Such a cut in Spring would cost less than $100 in USA and 100€ in EU, would please Europeans for the reduction of price disparity and would leave room for a less painful $50 cut in Autumn, should it be necessary.







