Unique liberal IP policy. UW-Madison is unique among U.S. universities in that it does not claim ownership rights in the intellectual property generated by its faculty, staff, or students, except when required by funding agreements. (See here. Also see the full IP policy.) This is great because it means you and your students retain the IP of your invention in many cases.
WARF funding — more than $70M per year. The Wisconsin Alumni Research Foundation (WARF) is a rather unique organization, which helps steward the cycle of research, discovery, commercialization and investment for UW-Madison. It has an endowment of $2.6B as of 2016 and contributes tens of millions per year to UW-Madison.
Shared (free) powerful HTC capacity. The CS-based Center for High Throughput Computing (CHTC) supports a variety of scalable computing resources and services for UW researchers and their collaborators, all free.