This has the potential for being a fantastic article, but since everything is quoted "tax-free", it's usefulness borders on poor. Modify the charts with a few more bars and some more math and this would be an excellent article...
For example, there's no sales tax refund for foreign visitors visiting the US, so a US price + sales tax is usually appropriate. Canada just got rid of their GST tax refund program for foreigners, so including PST/HST + GST is a must. Europe's VAT refund is never 100% of VAT once fees are calculated, and that assumes VAT is high enough to be refunded on the item. To add, US-based Internet/mail-order sales are tax-free, assuming the company has no presence in the ship-to state. Technically, foreign visitors to the US could order something online and have it shipped, tax-free to their hotel!
So, I wish the charts would show a few more values... For US prices, show values with no, low (5%), & high (10%) sales tax rates; for Canadian prices, only show values with low (7%-Alberta only) and high (14%) PST/HST/GST--since there's no refund or a way to get an item tax-free; for European prices, show prices only with "practical" VAT refund (say 75% of VAT) & full price (full VAT); etc. Show country-specific values only (i.e. don't show VAT in Canada or the US). Most people, myself included, have no idea what the tax structure is, refundable or not... Finally, show all tax-inclusive prices in USD & Euros.
For example, comparing the actual US$ price of the 2GB card in Canada vs. the US shows even bigger differences... While the US tax-free price is US$38.11 and the Canadian tax-free price is US$51.11, actual US prices would range from US$38.11 to US$41.92 (10% sales tax), while actual Canadian prices are US$54.69 (7% GST tax in Alberta) to US$58.27 (14% PST+GST). Someone shopping in Quebec would theoretically pay ~US$58 for this card but could go across the border to New Hampshire, which has no sales tax, and pay ~US$38...
Now, I know that someone could do most of the math above, but it's easier to compare "actual" prices instead of perceived ones... If this article was about gas prices worldwide, you'd show the price including taxes, since the tax-free price (that nobody can get) is about the same per unit of gasoline in most oil-consuming Western countries. Tax refunds should be considered to be "bonuses" or "rebates" and not automatically implied. Most shoppers will never see a tax refund...