Assuming you all already have the basics, (you know, a 1911, a 9mm, a .357 revolver, at least one mouse gun...), in order to complete the collection you need:
A Glock in 10 mm
A Ruger Mark II .22
A Desert Eagle
There are other things you also need to make any collection complete:
a few holsters laying around that you forgot what gun you bought them for,
A bucket or two of brass in your garage,
Several articles of clothing picked especially to accomodate concealed carry,
A wide assortment of targets, some already shot up, laying around in your garage or stuffed in your trunk,
Ear protection devices of several types, from the cheap foam plugs to the expensive electronic muffs,
.22 brass stuck in the treads of your boots,
Now you're a serious collector, shooter, gun person, congratulations!