From January, 2007, to October, 2008, median prices of sold homes in McKinney dropped less than 1%.
From October, 2008, median prices headed down about 3-1/2% to the April, 2009, timeframe, where they remained fairly constant until October, 2009.
From October, 2009, median prices rose about 6% to September, 2010.
From September, 2010, to March, 2011, median prices were almost flat with some minor ups and downs until March, 2012, when they took off.
From March, 2012, to date (May, 2013) median prices have risen about 11%.
These are median prices, meaning some houses changed more and some less over the periods in question. High end areas were subject to more fluctuation than more modest areas.
So, in brief, prices did not drop - they actually rose over the entire period, but started out dropping.