I'm planning on getting a 870 Express Tactical. But the one thing I don't like about it is the funky "door breach/stand-off device" choke it comes with.

I've read that it is bad to shoot the gun without a choke installed so I was wondering what kind of choke (Full, Modified, etc..) I should replace the stock one with, preferably flush fitting with the barrel.
The 870 will be for HD use and I will be using both slugs and buck-shot thru it.
Thanks.
A