well, it got the good side and the bad side.
if your 2006 income is very high, then, the advantages of having HBP is obvious.
A friend of mine, his husband income is 150,000 in 2004 and income tax collected is already 25000. He took all the money into RRSP and take out as HBP. Advantage here is he can claim almost all his income tax collected back. so, additional to the non-tax of the HBP portion, he is also get the income tax return as the pay back of his HBP loan. Very bright idea.
but if your 2006 income is just the normal range, put into RRSP and take out as HBP loan, the advantage is not clear and my opinion is not recommended. HBP is ideal for a long range home buyer, contributed to RRSP for 3-4 years, let it growth, and make it a wise choice.
In your case, you might have your own idea. but explore all your options before you make the decision.
cheers