Congrats! You have chosen the best undergrad in the world to go to, as one would be hard pressed to find a better combo of fun, academics, and successful sports teams with a beautiful campus to boot! My wife, brother, and I (resident, rising M3, and rising M1, respectively) turned down acceptances at "more prestigious" undergrads to come to UW-Madison, and it was unequivocally the best decision I have ever made!
1) How supportive are the professors and pre-health advisors? Are they generally open to helping students when needed?
Professors overall are very supportive, both from courses and in research labs on campus. If you want a smaller college feel and are going to major in bio or one of the sciences, consider joining the Biocore (honors biology) program - the program director and professors are extremely invested in student success and go out of their way to help each student realize their full potential. However, Biocore also happens to be very difficult, to the point where I felt some Biocore courses were as tough as some of my med school courses. Needless to say, the program provides a solid science foundation, and so will the regular track (Bio 151/152) option. Don't do Bio 101/102/Botany 130 - this is bull**** and med schools know its bull**** and it won't give you the foundation you need for the MCAT and beyond.
Unfortunately, in all of our experiences (my wife, brother, and me), the pre health advising is worthless. I was told I would never go to medical school after a freshman fall GPA of 3.4. Obviously, that was not true, as I did well the rest of my undergraduate career. Rely on SDN and older matriculating students for advice, but take everyone's advice with a grain of salt, no matter where it comes from (unless it is from a med school Adcom - their word is law!). Hopefully they have improved the premed advising since I was at UW-Madison, but I doubt it.
2) How competitive are the classes, and what are the average curving grades set to?
Mildly competitive, usually curve is around a B, BC, or C, depending on class and prof. Use Ratemyprofessor.com to look up profs and determine what classes to take based on those reviews to ensure you avoid the really difficult ones!
3) What is the overall environment like for pre-medical students (aka cutthroat, relaxed/supportive, etc)?
Not too cutthroat....supportiveness depends on the friends group(s) you establish - basically if you are a nice normal chill person you will have no problem making friends and finding a group to work with in whatever class you are in, as most students want to be collaborative. Again, the pre-med advisers don't really know what they're talking about, although maybe they will have gotten better by the time you start and/or need their help.
4) Besides academics, what else at Wisconsin has helped you stand out as a pre-med to medical schools? What are the pros and cons of the school?
UW-Madison has endless volunteer opportunities, leadership opportunities, research opportunities, and clinical opportunities. Everything you'd ever need to be an excellent applicant is right at your fingertips - you just have to go and get it. Also, there is a great work hard - play hard attitude at the school, which makes for a balanced lifestyle and normal people. Normal people interview well, whereas socially inept students who know how many ceiling tiles are in their favorite study room at their library usually don't come across as positively in interviews. As someone who has interviewed lots of applicants and helped shape the admissions criteria at my school, I want students who can relate to people, who I would like to work with, and who I could trust with the care of a family member (and, if research is a part of their application, I'd want students who I would be excited to collaborate with on a research project). UW-Madison has the resources and opportunities to develop the type of person who can be all of these things. However - the go-getters will take advantage of all that UW-Madison has to offer, while more timid (or directionless) students may get lost along the way or slip through the cracks.
I honestly can't think of any cons - my 4 years at UW-Madison consisted of constant, unbridled joy, and I wouldn't change a single thing about my experience! If given a chance to do it again, I would do everything exactly the same way.
5) Also, last but not least, would you say that the party aspect is a concern? I'm not a big partier, but at the same time, don't want to be left out of the social scene.
The party aspect is a huge positive part about UW-Madison. Work hard/play hard. You will not be left out of the social scene as long as you live in dorms your freshman (and +/- sophomore) year and live with friends for the reset of your time at UW-Madison. Learning how to have fun is important, as it will help balance you out, keep you sane, and be less of a robot.
Congrats again, and On Wisconsin!!!