The Ministry of Revenue issued a bulletin on the HST as it applies to new housing on June 18th. The province back-tracked and has restructured the HST as it applies to new housing. The tax structure is now a progressive tax structure with 2% being applied to the first $400,000 and 8% being applied to the incremental value above $400,000 up to a maximum rebate of $24,000 per new home. While it still represents a net tax increase, the new model is a significant improvement over what was initially proposed.
There is now also rebate available to rental housing (both investor & purpose built), seniors housing and a number of other housing types/tenures.
The province will harmonize with the federal definition of a 'substantial renovation' with rebate available there as well.
All purchase and sale agreements entered into prior to June 18th are grandfathered and there are some rather complicated transition rules that I'm not going to bother getting into in a general discussion thread with respect to the status of construction for projects that bridge the July 1, 2010 implementation date.
The federal government will now likely be under pressure to restructure the GST thresholds (which haven't been updated since 1991 to reflect new home price increases) to match the progressive structure that the province will be implementing.