re broadband: in the Madison area for small business and home, not so great, but not terrible either. Big players are the telco DSL services and Charter cable... none of which are particularly cheap, fast, or reliable, but within a tolerable level of service. Very limited areas of the metro area have access to direct fiber services like AT&T UVerse. As for large business and academic connections though, there are some big pipes to tap into... UW and state government have some heavy duty net infrastructure, including extensive linkups to the "Internet2" academic network.
re taxes: In Dane County (where Madison is located), sales tax is actually 5.5% And if a Regional Transit Authority is created in the not-too-distant future, the plan is to fund that through an additional sales tax (kind of odd to fund an RTA with sales tax, but that's a different conversation all together). Anyways, 5.5 is cheap compared to the exorbitant sales taxes to be found around Chicagoland.
Madison is often a highly rated place to live and work, but lots of us who live here consider it a bit overrated... Wisconsin winters detract from the city's charms a whole lot.