Best sites for booking cruises and other tips too

I am always asked who I book my cruises thru.  Below is my process:

1. If I know the destination I want I use www.expedia.ca to start as they typically will list prices/On Board credits (OBC's) at the same price/credits offered by the cruise line. But the difference is they have the list of all cruises going to the destination I want at the time I am looking at.   If you are using an expedia travel rep sometimes calling them after you look online will help you get additional OBC's if they have a "group" (meaning the have a block of cabins reserved on that ship that they want to sell) or even a slightly better rate.
2. After I have found the cruise or cruises I am interested in I then use a few other sites that specialize in cruises only - www.crucon.com, cruises.ca, onlinevacation center etc. Note these are in US $ but sometimes the prices are still significantly better even with the exchange and the OBC's are also more. On a recent booking the cost of the cruise was 35% less even after the exchange for the balcony, and I received $200 OBC versus $50 offered by the cruise line.  Again this booking was one of their "group" bookings.
3. I typically book/put a deposit on cruises that I really want to do about 4 to 6 months before the cruise as this has been when the good rates on the cabins have come up. Deposits can range from $50 for NCL to $450 for RCL and Holland America.  You must pay the full amount at approximately 75 days before the cruise.  Note good travel agents usually do this at the 90 day mark to make sure the booking is secure. 
4.  Should you book the flight thru the cruise line? ... most of the time I say no except for transaltantics or transpacifics where the starting and end points are different.  The cruise lines can typically beat the two one way ticket prices but not always - check online first. One the bad things about going thru the cruise line is that they will do a non-stop to go to the starting point of the cruise but the way home is very often a 1 stop adventure.  I have had a few bad experiences where I almost missed the second flight due to delays for the first leg. 
Hope this helps