By DAVE MONTGOMERY and ANNA M. TINSLEY atinsley@star-telegram.com AUSTIN -- One of the most intensely fought primaries in modern Texas political history arrives today, with incumbent Republican Gov. Rick Perry battling U.S. Sen. Kay Bailey Hutchison and newcomer Debra Medina in the spotlight race.The prospect of Perry -- already the state's longest-serving governor -- being forced into an April runoff has drawn national attention, but it's only one of many hot races up and down today's ballot.