My two cents worth:
Venture One - a great program. I hate having to charge Canadian bidders more shipping than to the US, but with venture one, I can get a cheaper expedited mail rate AND include $100 worth of insurance for free. The package gets there very fast and your Canadian customer thinks you're going that extra mile for them. Also - Expedited prices to the US can sometimes surprise you, depending on the state you're shipping to. 5% off helps quite a bit!
Seller Manager Program - USE IT! I started printing off shipping labels with the program - and my packages have been delivered way faster than when I was hand writing them out. Not only saves me time, but the automatic sorters read these packages better and get sorted and delivered faster. My shipping and packaging time has also been cut into a 1/3 since I started using this program. No more spread sheets, data entry to keep track of auction, etc. Highly recommend the program - I had quite an adjustment time with it - but I just love it now.
And the last one I'll post today - do all your shipping from a Canada Post outlet. Search around if you have to, but it's well worth it. With Canada Post - every dang small package was being measured, they are slow and my shipping costs were through the roof. I realize they have to do things by the book, but it was too costly for me. I switched to a local Shoppers Drug Mart, and I haven't looked back since. The girls there are great - they give me breaks on the shipping, more packages go through as lettermail, they are very fast and they don't measure every dang small package for minimum density. They now know me, they know my shipping preferences, they give me tons of extra shipping stickers and forms so I can have them all ready when I get there and we squeeze some things through for cheaper rates. Works for me. Canada Post will give you the forms and stickers as well in advance if you ask.