Lol. A $200 drop in base price, versus a $20 drop in base price (in reality it was two $100 price drops versus one $50 price drop but Sony fans don't like that so its been reworded for their ease of understanding). If its going to take that for Sony to compete I think it's clear they wont be able to keep it up.
Coming up this year (starting very soon) we have two strong line-ups for two strong consoles. Even before all the delays started being announced I though MS easily matched Sony's line-up for quality, and now FFXIII and GoW3 delayed with GT5 likely to follow, I think it matches it for system-sellers as well.
It is quite obvious that PS3's victory this week in NA was due to the strong shortages the Wii and 360 are facing, which are forecast to continue to the end of February for Microsoft, and the end of time for the Wii.
With the only complete version of GTAIV on Xbox 360 in April, a large advertising budget, a price cut imminent and new bundles/SKU's apparently being the cause of the shortage, I'd say the Microsoft machine will be fine.