Hmmm, have to get permission from the wife to add a couple, but my hard way 8 would be:
.22lr
.223 Remington
6.5x55 Swede
.270WSM
.357 Magnum
9mm
.375 H&H
12 ga.
I only have 5 of them currently, and not really sure I "need" the .375 H&H, but for top end stuff, it would need to be available. I like the .223 in both bolt action and semiauto, currently own rifles in the 6.5x55 and .270WSM. along with several .22lrs and 9mm and .357 Mag (which also handles the .38 spec.)