OK I'll play:
1.- AR-15, select-fire, suppressed Mk.18 clone
2.- AR-15, 18" Mk.12 Mod 0 SPR
3.- HK MP5A5
4.- Thompson Submachine Gun
5.- FN Mk.48 Mod 0 (7.62mm version of the M249 SAW)
6.- FN-FAL
7.- AKM
8.- AK-74
9.- AK-105
10.- FN SCAR-H
11.- lever-action .30-30, either a Winchester 94 or a Marlin 336 (either one is fine, as I like both)
12.- Mossberg 590A1
13.- Benelli M4 Super 90
14.- Springfield 1911A1 Loaded, stainless
15.- Sig Sauer P226 Elite, suppressed
I could have all my dream guns if the OP had said 25 instead of 15, but I think all my bases are covered with the above list. I would only add a CETME-L, Mosin-Nagant, Dragunov SVD, Ma Deuce, and my Henry .22 lever-action. And an SKS or two.