Fiscally conservative as such things are generally reckoned; socially conservative too (low ACLU rating, supports the drug war). Fairly standard-issue Republican in my opinion. People with strong pro-life leanings would probably consider him an improvement on Specter; to my mind he'd be more of a side-grade, better fiscally but less interested in civil liberties and the rule of law. I'm still hoping for a decent paleolib or paleocon aligned challenger.
It's also not clear that Toomey will run. He was making noises about stepping down after Peg Luksik entered the race.