I just went throught the whole app process (in ortho) for the upcoming match and am canadian. Your nationality does affect you, it's just hard to tell how much. I'm sure i got interviews at certain places just because i was canadian (and qualified ... but lets face it, pretty much everyone applying is qualified). Other places i talked to on the phone wanted nothing to do with the visa business (which, incidently, is against the law). I don't think its really their policy, just that most places lump needing a visa in with being an FMG eventhough they are not always the same. Either way, it makes a HUGE difference where you do your aways. DO NOT DO AN AWAY AT A PROGRAM THAT DOESN"T SPONSOR AN H1B VISA APPLICANT. This means, all the programs in mass. If you want more info, PM me. Good luck