$600/month for rent seems doable in parts of the South. You might be able to spend even less on rent if you get a roommate or rent a room in a house. If I were single back in medical school, I'd have rented a room in graduate/professional housing (as in a house with mostly grad students and professionals--not on-campus graduate housing). It's what I did when I was living in Berkeley, and that cost me about $650 with utilities, and while my room was pretty small, it was a pretty nice house. So I think you could spend even less in the South for something similar. It was relatively quiet, surrounded by smart/motivated people, but also lets you get away from all the medical stuff you'll see all day. But some people prefer medical student roommates.
$250/month for food sounds doable to me. If you eat out it will be more, but if you're really thrifty I know some people spend even less. Don't forget a lot of medical school get-togethers resolve around food. And especially for the singles, around going out to bars. You'll probably want to add an "entertainment" budget, because the odds are you'll go out at least a bit.
I usually budget $2000/year for car maintenance, but I have been fortunate to rarely need to spend that much most years (some years it's a few hundred, some years I reached that $2000 limit). So your estimate is probably OK, but it depends on how old your car is, if it has any current known problems, etc.
I think you could get away with spending less than $1000 on clothes. Dockers ($20-$25/pair when on sale) and Kohls is a great way to be dressed up for the wards and comfortable but save money. If you want to be thrifty, I find 3-4 pairs of Dockers/year works well before they start wearing out, and I like to have 7-14 dress shirts (which last longer than a year, at least for me). I found second-hand stores are great places to get ties--they're about $2-$3, and you can find some nice ones (as well as some ugly/gross ones--so look at them carefully!). You just have to assume there might be only one or two decent ties worth buying, at best, each time you visit a second-hand store, so it takes a while to build up a collection.
If you dress nicer than I do then you'll spend more--but you really wont need many nice clothes until 3rd year. You could probably do fine with two pairs of nice slacks and 3 dress shirts/ties during M1-M2. Honestly, you'd probably be OK with just one pair of nice slacks and two dress shirts/ties. Unless there's a dress code for lectures...
$50/month for a phone sounds reasonable, assuming you already own the phone or got a free one. During M1 and M2 I don't think there's any reason to have to have a smartphone (it's a nice luxury, but really not necessary). I didn't buy one until intern year--up until now I just used a cheap phone with no data and an iPod touch (my med school and hospital had WiFi) to access e-mail, as well as Mircomedex/Epocrates (both can work offline) and MedCalc. Nearby computers handled anything else I might need. Even now I rarely use cellular data on my iPone--I just wanted to consolidate my phone and iPod into one gadget, and I also thought a smartphone would look a little more "professional."
I'm not sure what "household and hygiene" really refers to. If it's soap, deodorant, 409, etc, then I just include that in my grocery budget.
It's worthwhile to borrow extra your first year so that you have a little bit of a backup in case of a rainy day (you can't always ask the financial aid office for extra funds--I think October of each year is the latest you can request additional funds). Plus that could give you some flexibility while you figure our what your budget will really cost you. I budget a certain amount each month, but little things always come up here and there that you didn't budget for, so a miscellaneous category is always helpful.