I think a job at a large tech company would be my ideal first job. Having worked at both types of companies, I think the level of professionalism is higher at large corps, they know how to deal with junior level employees, the pay will be better, and so will job stability. Starting out at your first job involves a lot of social anxiety in a way, and I think it's easier to deal with the boring mega-corp socialization than the dorm-like atmosphere of a startup.
Having said that, it's important to work on projects that are impressive on your resume. Fixing bugs is fine, but 3 years of generating graphs for financial reports, or externalizing strings to internationalize an app will not help your career. Startups will definitely offer you challenging projects, but so can large corps, and often they'll let you take a bite you can more easily chew.
Edit to add: I think an important thing is to consider, will I enjoy working with these people and will I be able to satisfy their expectations? Especially make sure you and your boss will get along. This along with getting impressive projects are the most important things. But all else being equal, I'd prefer a large corp over startup for your first job.