Hey osirus,
I actually think really highly of the Simon School. It seems to be underrated by many applicants, but I think Simon gives a lot of students a "foot in the door" at many top companies. Especially if you're interested in finance/banking and if you're looking primarily in the Northeast, Simon gives you a shot at almost any "top" firm I can think of. The difference between Simon and a top-ten school is usually more in the number of jobs that those firms hand out on campus. For instance, Goldman may make 40+ offers at HBS, but more like half a dozen at Simon. (Of course, Simon's a much smaller program.) So, you may have to hustle to get one of those jobs, but I'm a firm believer that the cream usually rises to the top.
Beyond that, assuming you got your foot in the door and landed a job at a high-caliber firm, then the rest is really up to you. That's another thing that many applicants miss: How you'll do in your career over the long-term depends far more on how you perform and who you make connections with, rather than on what school name is on your resume. Of course, a "better" school gives you access to a "better" alumni network, which may always help, but even that matters less than what experiences you gain and what accomplishments you can start to rack up in the first several years out of business school.
In that respect, the working world and the admissions world are not radically different: What undergrad school you went to and what company you work for now certainly matter, but what's even more important is what impact you've had on the company and the community around you!
Scott