Right now today (could change tomorrow!) I'd have to keep...
.22
12 ga
6.5 X 55 (can I keep 5 of 'em?)
8mm/06
and still need to buy a .375 H&H

But I'd probably have withdrawal or die if I actually had to part with my 243, my 7 X 57, my 7.62 X 39's, my 308, my 300 Savage, my 30/06, my (sniff) 8mm/06, or my 20 and 16 ga's

They all are used, just not necessarily "needed"