Heres my top list.
.22LR
.22 mag
.22 Hornet
.223
.22-250
.243
6.5 swede
.25-06
7-08
.270
30-30
.308
30-06
7 remmag
300 win mag
.338 win
375 HH
45-70.

Everyone of these guns, ammo is readily available and at cheap prices.
They all have a rival that does what they do a tad better, but at what price, barrel burning and shells that cost and arm and a leg, or are hard to find. for the average Joe like me ,this list is all I would consider for purchasing. One of my best friends owns a .300 win mag and he is caught up in the bullistics, he wants a new gun, until I take him in the sporting goods store and let him try and find those new shells or he see's the price of them.
I just dont see the need, not if the price of shells are going to cost twice as much, or unatainable.
Carry on.