Sports Arenas, etc. are bad economically, and the tax-payers should never have to foot the bill. New arenas bring in almost no jobs, since they have like 50 insanely high-paid people and then a bunch of people that only work during game days (which is less than half a year, 20 days or something for NFL).
Check this out if you want a good explaination on why stadiums suck:
http://www.heartland.org/pdf/madness.pdf