I am an engineer also living in Vancouver, and during my career I've investigated the pros and cons of moving to the US, including visiting a number of cities and talking with people who work there. I know a number of people who have moved south, and I can relate some of their experiences here. I also made in the salary range that you described, and just happen to be working on my tax return this weekend, so I know pretty accurately how much I send to the government.
My objectives are first to clarify the real tax rates in Vancouver by informing about my personal tax situation, as it is close to the example that you gave; second, I will give some advice to consider before choosing to head south.
According to my 2003 tax return, my total income was $72k (including salary, bonus, a very small amount of taxable benefits, all medical insurance). The included medical insurance would have cost $648. I was taxed $13866, or 19%.
I made a $10k Registered Retirement Savings Plan investment, which means that I was taxed on a 'taxable' income of $62k. (For the information of the non-Canadians, an RRSP is a tax-sheltered investment account.) You would probably invest at least that much money in any case. However, in the unlikely event that I had not made investments, then my $13866 in taxes would have been 22% of my total income.
Groceries and housing make up by far the largest portion of my expenses, as it does for most Canadians. Neither is taxed (I rent). There is a 7% federal tax (GST) charged on almost every other consumer level purchase in Canada, plus in Vancouver there is a 7% provincial tax (PST) on many (not all) consumer level purchases. I estimate that I paid $750 in GST and PST at the most. The average person in Vancouver with my income would probably spend a bit more.
A homeowner would have to pay, on average, $1800 in property taxes in Vancouver.
To summarize, I paid about 20% ($13866 + $750) of my $72k in taxes. If I chose to own the average Vancouver home and make the average consumer purchases, then I would have paid about 23%.
Not even close to 40% (or the 50% claimed by some sources that I have read). You can plug the numbers into the 2004 tax forms and see for yourself. I can think of how extreme examples and playing with numbers might produce 40%, but I won't get into that here.
Now I would like to share what I have learned while investigating the pros and cons of moving south.
First, let's look at financial factors, starting with taxes.
In addition to learning the federal, state and municipal taxes for the location that you are interested in, you should find out what services these include. I learned that in *some* US communities, you may have to additionally pay fees for unexpected things such as garbage collection, tolls on local highways and bridges, and neighbourhood security patrols (these are in addition to regular police).
Next, investigate what the cost of living is in the community where you believe that you would be moving. In addition to paying rent or buying a home, learn other costs such a utilities and food prices. I was surprised to learn that a home high speed Internet connection in California may cost $US75, compared to $CDN25 in Vancouver.
The biggest financial consideration could be insurance, especially your personal health insurance. It will definitely be much higher that what you would pay in Vancouver. If you were to develop an illness or disability in the US, your insurance may run out before you recover. If you were to develop a chronic illness, you may be uninsurable. If you were living in a state where you cannot be denied insurance, you may have to pay premiums of $10k or more. This would affect your employability, even if your illness or disability did not affect your ability to do your job.
I know two physiotherapists in Ontario that were lured to Eastern states by higher salaries and lower taxes, but they found that they were saving less than they would if they were practicing at home at lower salaries. It was one of the reasons that they moved back. I know a few people working in IT that have moved to various states (Texas, Virginia, California, Washington). Most are content with their financial situation, but the one in California has found living costs to be way more than anticipated and is barely saving any money. However, she stays for the lifestyle.
Lifestyle is the other major consideration. If they are potentially important to you, consider commuting time from a residence that you can afford, public transportation availability, pollution, proximity to the type of recreation that you like to do, "friendliness" of the community, political environment, crime rate and personal sense of security.
In addition to comparing US locations, I recommend doing the same for other Canadian cities. For example, the cost of living is much less in Edmonton than it is in Vancouver, so you may end up saving more there than you would in some US cities that you are considering. I know engineers that have moved there for that reason.
In summary, before you sign anything, add it all up and talk to others in your field who have moved away. Don't just talk to the recruiters.
Good Luck,
Paul