” When I moved to Oregon, I did not establish residence and my legal address is still in Michigan.”-->I assume that your either a US citizen or a US resident alien UNDER either US Tax law or UN INS Rules. Then I guess at that time, you had to file your MI return as part year resident of MI on half of your MI income as a political consultant/ nonemployee and also had to file your OR return as a part year resident of OR, too as there is no reciprocal state tax agreement between OR and MI.
“ My wife is Canadian and has supported me during my spotty employment in Oregon, though her employment doesn't really "count" for my US taxes. She lives in Canada and her income is Canadian. Should I still apply as married, but filing separately?”--> Yes. You can STILL file your return either as MFJ or MFS if she agrees to be subject to US taxes on her world wide income. If she agrees to this, attach a signed joint written statement to that effect to your return. You can take a credit for any foreign income taxes paid using Form 1116. It doesn’t matter where your spouse is. You can claim an exemption for a nonresident spouse, withhout a SSN. You'll generally pay less tax on a joint return. And there is no requirement that she lives in the US. To file with a nonresident spouse as MFJ, you must file a W-7 application to obtain an ITIN number for your Canadian spouse( if you want), this application should be sent in with the 1040 form you file, to the address shown in the w7 instructions; since your spouse does not have an SSN, she will need an ITIN to file a joint return. I guess: a spouse can never be a dependent. And, as well there is no where on a HOH return for claiming a spousal exemption. Your only way to claim her would be to claim her as a "qualifying person", unfortunately nonresident aliens do not qualify as qualifying persons.
“For these purposes, I assume I count as "single" because she is not my dependent, but we were legally married in September and I'd like to claim it as such (if I file my taxes as single, it could jeopardize the genuineness of my application of permanent residence should the Canadian government look into my tax history).”-->No; as you are married, filing your US return as Single is TECHNICALLY wrong; however, if you need to file your US return as MFS( as your wife is in Canada) in lieuof MFJ, then you may file your return as single; the IRS doesn’t care, I guess, because there is NO difference of taxation rate between MFS and single status, as you can see. But if you and your wife want to file your return as MFJ, then you CAN’T file your return as single.
“All in all, I made a meagre amount of money in 2010, I'll probably have to pay in, but I'm still unemployed. I just don't want to be audited.”-->No I don’t think so either; the income guidelines for most people are fairly easy to follow if you know some facts. For example,as single under the age of 65 yu don’t need to file this year if your AGI is less than $9,350;$5,700( standard deduction)+$3,650( personal exemption)=$9,350 UNLESS you are subject to a federal tax refund.If you are 65 or older, then your gross income has to be $10,750 or more. If you file your return as married filing together, then you need to file your taxes if you are both under the age of 65 and your gross income is $18,700; $11,400( std ded ;$5,700*2)+ $7,300($3650*2) or more.I guess if you neeed to file your return, you May file 1040 EZ FORM, the simplest form as long as your filing status is single or married filing jointly; You claim no dependents;you, and your spouse if filing a joint return, were under age 65 on January 1, 2011, and not blind at the end of 2010; you have only wages, salaries, tips, taxable scholarship and fellowship grants, unemployment compensation, qualified state tuition program earnings. please visit the IRS Website here; Tax Topics - Topic 352 Which Form – 1040, 1040A or 1040EZ?