No consideration for the SR-25?
Edited to say: Ooops, didn't read your post very well, SR-25 is not a first .308 type gun (very $$$). I really like the FAL. I don't think it's accuracy potential is that of the AR-10 though. I once attended a lecture on the FAL from Peter Kokalis himself, and they found that point of impact changed from round to round in relation to the rounds position in the magazine, though the first round placement was always the same. The FAL is more versatile I think, due to the adjustable gas system, magazines are cheap and plentiful as are spare parts. Heck, you can buy FAL/STG-58 kits and build your own on the cheap. AR-10 gives you more prestige. I have the FAL and SR-25, but still want the AR-10, naturally. My ultimate fun .308? A DSA built select fire paratrooper FAL with folding stock and 12" entry barrel.
For your first .308, get the FAL first, then go for the AR-10 later in consideration of affordability and availability/utility. Come into a lot of money then you can get the SR-25 and tease the AR-10 owners.