If one barrel length could do it all everyone would a shotgun with one barrel that perfect length. It's very quick and easy to change barrels on any pump shotgun. I recommend a Mossberg 500 combo. It has a 24" rifled barrel and a 28" accu choke barrel. You can find the Mossberg combo about anywhere. You can even order one from Walmart. The 500 combos run around $350 plus tax.
I own both a 500A (12 ga) and a 500C (20 ga) Mossberg 500 combo. They both are very accurate. I made the 500A into a dedicated slug gun. It has a 4x scope on it and a single point sling. I did away with the williams sights that came on the rifled barrel so I could use a low profile scope mount.
If you can't afford a 500 combo here is a great deal on a stevens combo. They are out of stock right now but this is an item Buds carries regularly. Two of my friends have bought one recently.
Mossberg 500 combo