M1 Garand?
I recently went through the same mental discussion. I'm no expert, but here's some of the reasoning I went through before deciding.
After examining CETME's at a few local shows I ruled them out. If nothing else, the fit, finish, and rough feeling of the guns left me unimpressed. They were, however, very affordable.
The PTR-91's look very promising, as do the G3's and HK91's. They are all expensive, though, and I have been told that they are very rough on brass, making repeated case reloading a risky proposition. Maybe someone else with experience could chime in on that.
The M1A used to be affordable but even a Springfield GI gun is at or above $1000. The high cheek weld required for eye-scope alignment requires a serious cheek-piece or a new stock. For irons it isn't an issue. I have been told that the ejection system is not as rough on cartridges as the HK's, but that reloadable case-life is nowhere that of a bolt gun.
The FAL is the right arm of the free world... what else can you say? Examples can be had for well under $1K and the adjustable gas system can easily adjust to meet different ammo needs. Magazines and parts are readily available. The sights don't impress me, but those can be changed. Also, there are several variants to suit your particular needs.
Corrosive ammo is not a huge issue with me, since I clean my guns regularly anyway.
Eventually, I bought an M1 Garand. Sure it's not a .308, but quality M2 ball ammo (in clips) is cheap and plentiful from the CMP right now. If that would change in the future, converting a Garand to .308 is no big deal. The lack of a protruding box magazine makes it much more comfortable for me, particularly shooting prone. It may not be high-capacity but 8 rounds of M2 at a time should be plenty for my needs. As far as case life is concerned, a regular posted on the CMP forum stated that most of the trauma caused to the case is at the mouth, which is easily fixed during resizing. I have yet to reload for it so we'll see how that pans out.
One downside to the Garand is that it is not really intended for commerical 30-06 loads. These loads operate at higher-than-M2 pressures and can eventually bend the operating rod. Capacity might also be an issue for you.
As an upside, it has been battle-tested in every imaginable theater and proven to be a rugged, dependable, reliable piece of equipment.
That all said, I'd still like an FAL or possibly an M1A someday down the road.