I'd say go with an M1 Garand.
After all, it's the "greatest battle implement ever devised".
Also, if you're shooting paper, you will not be disapointed with an AR-15, either.
It's the most expensive, but if you decide on a complete rifle in 5.56, you can purchase a 7.62 NATO upper and have a real tack driver in both calibers.
My semi-auto choices:
1) US Rifle Cal 30 M1
2) AR-15
3) M1A (16" SOCOM)
4) FAL (L1A1)
5) G3, or CETME
6) AK