As the owner of 'em all at one time or another (M-14, HK 91, CETME, AR-10), I can without reservation recommend the FAL. I currently have settled on a DSA SA58 medium contour (metric pattern), and this rifle, if you want a 7.62 x 51mm, is overall without peer.
It carries well, is incredibly reliable, points well, mags are plentiful and cheap, ammo is plentiful and cheap, and it, most incredibly, it shoots 2" groups at 100 meters with anything I feed it, from cheapo CAVIM to Match ammo. (I'm still trying to figure that one out!)
If you want a .30 caliber, the FAL, particulary the DSA, is the way to go.
