More reasons off the top of my head...
1. The architecture of the buildings is classically gothic and beautiful.
2. Big university resources, smaller LAC-style attention to students (and AN EXTREMELY SMALL % OF CLASSES TAUGHT BY TAs - and when they are taught by TAs/Grad students this seems to be a good thing - e.g., the Writing 1 class).
3. Academic Flexibility -- Easy to switch schools within WashU and to double major/minor.
4. Amazing pre-professional programs and resources, especially for pre-meds through the renowned WUSTL medical center
5. The quality of your peers
6. Some of the best dorms in the country
7. Some of the best food for a university
8. Genuine Midwestern friendliness and helpfulness
9. Lack of cut-throat competitiveness amongst students, more collaboration
10. Easy access to metro and bussing (FREE!)
11. 2nd best DIII sports school in the United States
12. Professors are more undergrad-focused than other top research universities (but renowned in their research fields as well!)
13. Undergrads have limitless research opportunities.
14. Beautiful campus (where students are playing ultimate frisbee, football, or in hammocks on the quads).
15. Forest park across the street (HUGE park with free museums and such).
16. The Loop (great food and shopping) within walking distance of the university.
17. Humongous shopping complexes not too far away (by car, Clayton area?)
18. 3 large hospitals within the area.
19. Exceptional academic advising
20. Amazing diversity of the student body
21. Abundance of outstanding prearranged extracurricular activities available to student body (tutoring h.s. students, hospital volunteering, etc.)
22. Amazing merit scholarship opportunities not found at any school of WashU's caliber.
23. Central United States location that allows for relatively easy access from both the East and West Coast.
24. Hammocks all over campus. 'Nuff said.
25. Loads of brand new buildings and a strong commitment to construction and development...
26. St. Louis's fabulous music scene.
27. Crazy huge endowment that allows for lots of free trips to campus and subsidized FOCUS excursions and everything a student could want.
28. Summer excursions like ArtSci Weekends and FSAP that allow students to get acclimated to campus before Orientation.
29. Awesome Pre-O's!
30. Residential colleges that allow freshman to have connections to sophmores.
31. Really nice programs for frosh like FOCUS and Freshman Seminars and MBB, Text and Tradition, Medicine in Society...
32. They send you a lot of mail and you feel really good, especially when it's priority and you're like "OMG they spend $4.95 on ME!"
33. Outstanding Financial Aid
34. St. Louis has some fabulous food. The Hill, Ted Drewes, Tin Cup. Also the amazing Missouri Bakery with the best cheesecake I've ever eaten.
35. Involved and caring students (hirako, don_quixote, johnson181, balancedhelium, etc.) and parents/others (midwest parent; st2, fallenchemist; palmalk, etc.)
36. WILD (Kid Cudi and the Black Keys in a few weeks!)
37. Award winning and AMAZING a capella groups
38. The best dressed university chancellor in the country who has a bowling alley in his house!
39. The Bunny. Enough said.
40. Thurtene Carnival, largest in St. Louis, tons of food, games, rides. Greek life also plays a big role in the carnival.
41. The Holi Festival. Students gather on the Swamp for the school's largest water balloon fight. Everyone gets wet, muddy, and most importantly, everyone has fun.
42. The Gargoyle
43. Highest "Survey-per-week to Student" ratio
44. FLAT SCREEN TVs everywhere!
45. Smart kids yet no snobbiness
46. WUstock by the CS40 for free
47. Ursa's hot chocolate bar with 10 different kinds of hot chocolate, 6 kinds of homemade whip cream, and crepes on friday nights
48. Become a part of the best Baseball city in America (Just 5 train stops away from Busch Stadium)
49. Adjoined to the library is Whisper's Cafe - where you can go for your late-night studying or cafe food run!
50. If you're into any of the hard sciences: the best, top-notch, cutting-edge, fully-stocked laboratories and the myriad of research opportunities that come with them
51. The award-winning, always fresh and interesting StudLife
52. Moonlight Breakfast
53. Walking distance to The Loop, a bustling avenue of shops, cafes, and restaurants
54. Did I mention the gorgeous campus? Call it fairy-tale or robust and gothic, whatever you wish, but it is GORGEOUS.
55. Jazz at Holmes' Lounge
56. The Campus YMCA and the spawn of volunteer and community outreach programs, including the Social Change Grants
57. Gelato and crepes in Ursa's, Froyo at Bear's Den
58. Selectively chosen, fully trained, enthusiastic, and approachable Residential Advisors
59. Academic mentoring WITHIN the residential halls, in the form of selectively chosen, fully trained, and caring Residential Peer Mentors (for Writing, Chemistry, Biology, Physics, and Calculus)
60. New Dorms on the 40 have memory foam
61. Free pizza events all the time
62. For the premeds: A panel of premedical advisors who are always available, supportive, and effective. While they are available anytime, starting junior year the Pre-Health advisors begin keeping a very close eye on your medical school application process. Premed advising and workshops include mentorship on your personal statements, reviewing your medical school resume, and interview practice.
63. Bear Patrol, which escorts those late-night study-ers back to their dorms
64. Closed campus, probably one of the safest around
65. The newly opened Danforth University Center, with an array of eateries, its own formal restaurant, and the upstairs Game Room (includes Wii, I think)
66. Wireless Internet access virtually anywhere on campus
67. Friendly bus drivers who care about the students
68. Bon Appetit, which listens to the students' needs and concerns and hosts fun events (like that Willy Wonka golden ticket game last year)
69. Students who are tolerant and supportive of each other
70. We just won the 2010 Annual Jeopardy! College Championships. BOOYA.
71. The Lunar New Year Festival - Student dancers and musicians combine artistry and aesthetics to create a story about the Lunar New Year.
72. Many city events are subsidized for students by campus organizations like ArtSci Council. Examples of events include city symphony performances (freshman year I remember Itzhak Perlman was in town), plays, musicals, Shakespeare in the Park (summer), and more.
73. The BALLER Brookings Hall. Seriously, have you every stood in the parking lot, beneath that flight of stairs leading to the two towers of Brookings Hall, and know that you will soon ascend the path to greater knowledge?
74. WashU is one of the prominent hosts of the Vice Presidential Debates, including Palin vs. Biden, 2008.
75. The fact that it's WASHINGTON UNIVERSITY IN ST. LOUIS.