Just wanted to add that larryboy's assessment is pretty darn spot on. At least, his original post was exactly what I've encountered with my finances as a new attending.
Larryboy was being very generous when he dished out a starting salary of $160,000. I have friends in Pediatrics, for example, who started off $90,000 to $120,000. Ouch. Please keep this in mind. Some RARE individuals in Family Practice had starting salaries in the $240,00 range -- they were in unattractive, rural areas though, but if this is for you, then there you go. I would have probably done this had I gone into primary care.
As far as loans, just to give some perspective, I had no undergrad loans (full scholarship), but I accrued $240,000 in med loans (Subsidized, Unsubsidized, and Perkins). I currently pay $1600/month in loans. It's approximately 25% of my paycheck. It's tough. I'm still living rather inexpensively similar to med school (i.e. not using A/C or heat that much, bicycling to and from work). It does help to live less-than-modestly, yet there are just other little things here and there that you don't think about that cut into your income. For example, I got a $404 bill this morning for professional membership in an organization and a $200 invoice for another organization (yes, these are essentially required in my field or I wouldn't do it). Another example, I was required to take 3 board exams to practice ($1800 each, plus traveling expenses because board certification in my specialty only occurs in FL so you must travel there). Oh, I also need to pay for my 35 annual CME credits that are required to hold onto my board certifications. I also have to budget for furlough days (yes, you read it right), so I'm not really making the salary on the contract that I signed. Obviously, this is not a comprehensive list -- just a very tiny few examples.
Like larryboy, I'm not trying to deter anyone from medicine -- I just wanted to provide some numbers and food for thought for those interested. I think it's good to know what you are potentially getting yourself into, regardless of career choice.