I took Calc 2 my freshman year and didn't have strong feelings either way, but I also have heard mixed reviews from other students regarding the basic Calc courses (some positive, some average like my experience, and some pretty awful). If you do find yourself with a less than captivating professor, there are three things you can do to potentially make your experience better:
1) There are tons of sections of Calc 1 - 3 offered each semester, so if you find yourself in the first week with a professor you don't like as much, you can try to switch into another section during the add/drop period during the first couple weeks.
2) At least in my Calc 2 class, it broke down into two separate smaller discussion sections once per week. for other kids that weren't doing as well or wanted additional help, the discussion section was a much more productive use of time than sitting in the lecture.
3) Cornerstone (the free tutoring/help center) has tons of resources available, such as study groups, help sessions before exams, and peer-lead team learning (aka PLTL).
I have heard great things about the upper-level courses and professors in the upper-level courses, though. The Math department has a lot of options for specializing in certain tracts in mathematics... the 5 concentrations you can choose between are:
1) Traditional Track
2) Probability and Statistics emphasis
3) Applied mathematics (most students following the Applied track combine it with substantial work or a second major in a math-related area such as physics, computer science, or engineering)
4) Secondary Education (well suited with a second major in education)
5) Economics Emphasis (well suited with second majors in finance or economics)
After you take the foundational calc courses, each of those concentration tracks requires somewhere between 7 and 10 classes. There are
40 upper-level (300+ level) courses offered in the Math department, which seems like a lot to me. The Math department isn't exactly the largest department on campus in terms of students majoring it, so to offer so many classes with so many professors probably means that the average class size in Junior/Senior level classes are really small class sizes.
By petition with a professor, you can also take some of the Graduate-level courses, as well as independent study with a professor.
There is a Math Major's lounge in Cupples 1 (the math building, in the Quad), which has seating, kitchen stuff and appliances, chalkboards, and wireless internet. There was a dedicated Math library which was one of Wash U's 14 libraries, but this year it was merged into the central Olin Library on campus.
This is interesting, I'm copying it from the department's website, regarding the national Lowell Putnam Math competition: "Washington University's performance in this competition over the years has been very good. Since 1976, our team has placed among the top ten nationally in 19 of the past 33 competitions, and in the top five for 11 of those years. In the 20 competitions 1989-2007, 27 different WU students have ranked in the top 100 a total of 48 times."
This is a listing of recent Research projects that undergrads have done in the Math department:
Undergraduate Research
There's a study abroad program for math majors in Budapest, Hungary.
So, while the reviews for the basic Calc professors don't seem to be raving reviews, I think that the breadth of course offerings, favorable reviews for upper-level classes, very small class sizes in the advanced classes, and plethora of undergrad research opportunities seem to be more of the highlights of the program.