It is hard to beat the 870, I got two for my son, one is set up for deer with a rifled barrel and receiver mount holosight, and the other for upland birds.

I picked up a new Nova with bird barrel (includes 3 chokes) and cantilever deer barrel for $400 on Gunbroker. It is a bit heavy with the 3.5" receiver, but with the synthetic overstock is pretty bulletproof, and the stock is extremely easy to handle, even when wet. The 870's a great gun, but I personaly prefer the feel/handling of the Nova stock for myself.