Harper has NOT run standard or even acceptable sessions of parliament. He has made three controversial and questionable dissolutions of parliament since he took power less than four years ago, in February 2006:
(1) September 2008 - Harper dissolved parliament and called an election (or rather, forced the Governor General to) despite his own law, passed in 2007, that created fixed election dates every four years. He did this because two months later Canadians would have known that he had created a structural budget deficit.
(2) December 2008 - Harper prorogued parliament to avoid a non-confidence vote.
(3) December 2009 - This prorogation.
This prorogation was NOT done so that MPs can watch the Olympics or create a budget or have time to think. Parliament was prorogued because the special House of Commons committee focusing on the 2006-07 treatment of Afghan detainees had attained such overwhelming evidence that they held an emergency meeting on December 14 and then announced that they would widen the inquiry. On December 15, rumours started swirling that Harper would prorogue parliament.
It is NOT the case that Harper's use of prorogation is the same as the 104 other prorogations in Canada's history. Other than incidents in 1873 and 1926, prorogation has not been used to avoid being accountable to parliament.
It is NOT true that Chretien's 2003 prorogation was the same as this one. (1) In the 2003 incident, Chretien prorogued when Martin was voted in to replace him as PM, so the parliamentary agenda needed to be reset, which is the purpose of proroguing. (2) Chretien had a majority, so there was no contempt of parliament. Yes, it was probably a side benefit for Chretien that he got to let Martin take all the heat on the A-G's report, but that wasn't the main purpose or justification of the prorogation. See this news article from the time.
Update: Only in Canada: Harper's prorogation is a Canadian thing