Funny that you said three shotguns because I have dozens of handguns and dozens of rifles but only three shotguns :
1) Remington 870, extended magazine, 6-round sidesaddle
2) Saiga-12, Pistol grip, folding stock, Shark brake permanently attached for total barrel length of just over 18 inches with a number of 10 round magazines and 20 round drums.
3) Replica of a Colt 1878 double barrel with exposed hammers.
These three pretty much cover my interest in shotguns.
I am hard pressed to come up with another shotgun I need to own - but I suppose I would buy a Browning A5 if I found one at a nice price.