My understanding is that which school you go to has little to no effect, other than I've heard some schools prefer not to take their own students for internships/residencies (although I'm not sure how true that is). Any AVMA-accredited school will set you up well for an internship or residency, although obviously if your school doesn't have a specialist in the field you're wanting to go into, you'll have to do a bit more legwork to make connections. I've been told the main things looked at are your GPA, class rank, experiences and letters of recommendation.