As a business owner this crap terrifies me. Washington State was looking at changing their tax code retroactively to get more money from Microsoft, luckily level heads (and I might presume, extensive lobbying) prevailed. I can't plan today for what yesterday's laws will be tomorrow.
That will work until one of the Microsofts of the world decides it's more cost effective to move everyone 2 hours drive north to Vancouver than it is to pay this giant bill. The US is quickly going to learn that there is a rather modern country to the north that isn't in the same financial distress as Europe or most states are. I'd imagine given that, this line of thinking would probably play itself out pdq.
Vancouver, BC has barely any tech industry (a few software companies like Business Objects, and EA Sports are up there, but nothing meaningful), and the taxes are high. British Columbia has one of the highest tax rate in Canada. One of my Canadian friends told me that the 50% marginal tax rate started around $65k, although I haven't double-checked this for accuracy.
You can't compete between Washington State, with no state income tax, and Vancouver, BC.