As I've said about ISU fans who are crazy if they don't think ISU to the Big 10 is an awesome situation.. so are Hawkeye fans who don't feel the same way.
Speaking purely for football, how is trading that non-conference game for an in-conference game at the end of the season during rivalry week a bad thing? That should be seen as a great thing by both fanbases. There's at least potential for a bit more national exposure there, especially if one or both of the teams are having a great year.
On that same token, one more game against each other every year all of the other sports.
But if there is actually academic consideration involved here, ISU (between academics and geography), should be in consideration. Jon is right about the AG part of things, of which I believe ISU would be a leader of in the Big 10. ISU would also join some great engineering institutions in the Big 10 like Illinois, Purdue, and Northwestern, and certainly ranks with or above those schools (Illinois is probably highest rated, I think..). And if you want to talk about grant money... engineering is where it's at. So between the fuels industry (TONS of money), and engineering in general.. there's more firepower with ISU joining the Big 10 in giving that conference leverage for grants.