A couple of things to add about stipend taxes:
1) Most programs consider your stipend income non-reportable, so they will not send your pay information to the state or federal government. As it's legally written, you do owe taxes on your stipends, but you only have to report income that was not used for necessary education expenses (required textbooks, computers if required, steth, step 1 fees, etc). Subtracting out those expenses saved me a good deal of money.
2) If you expect to owe the government more than $1,000 in any given year, you should file quarterly taxes. While they won't necessarily fine you, the government is legally able to slap you with a fee for paying such a large sum all at once.
3) Talk to other students in your program, they know what's up. For example, students in my program informed me that Oregon allows you to deduct all of your room and board expenses on state taxes. Thanks to that, very few if any of us owe money on state taxes if we know to claim the credit.
4) It may not be a bad idea to take on a very part time job at some point. Every once in awhile, the government adds new tax credits that are applicable only to those with actual W2-granting employers. The money you save is worth it if the job is right.
For what it's worth, I take home about $1550/month after accounting for taxes. It's easy enough to live on that in Portland. I share a rocking 2 bedroom house with a roommate, and we each pay less than $500/month including utilities. It also helps that I'm one of the carless, Portland hippie-folk.