That's a pretty open ended question.
What action do you prefer (pump, bolt, auto)?
What's your price range?
Rifled or smooth bore?
Scope or iron sights?
I use a Benelli SuperNova with a 20" Badger rifled barrel. 3x9 scope. Very accurate using Remington Accutips slugs, 3 deer taken @100 yards, 2 being neck shots.