I think MS will stick with the current pricing.
As mentioned above, the price lineup Sony is choosing doesn't force MS into a corner, that combined with MS having a much better holiday lineup (IMHO) means that they can still be very competitive with their 3-tier sku.
Plus, when MS does their next round of discounts, I think that would force Nintendo to as well. My prediction on this is not until next summer will we see all three hit a round of price reductions.







