IMHO, the first thingone shouldconsider is WHATYOU ALREADY HAVE. I believe wholeheartedly in "cartridge spacing" i.e. spreading them out rather than getting a bunch of rifles that are essentially the same thing. For example lets say a 4 gun battery,if you have a 308, a 30-06, a 7mmRemMag, and a 300WinMag you are not near as diverse and capable of "matching tools to the job"as some one who has a 243, a 30-06, a 338WinMag, and a 375H&H.

If it is ones first long guns, then
22LR
12 Gauge
30-06.

Just because.