One thing that struck me when reading this was that, despite the times when it might make a lot of sense, I virtually never put a low stat into Int. The reason for this is that I'm a pretty smart guy (I'm not trying to brag, but I do have a decent gift for problem solving and especially strategic and tactical thought) and I'm only a marginal role-player. I cannot stand to sit by and play a dumb character when the smart choice seems so obvious to me as a player.
That doesn't mean that all my characters are geniuses either (since I'm not a genius, that's even harder to roleplay than a dummy). But I rarely put a stat lower than a 10 in Int.
Oddly enough, I tend to put a higher score in for the types of characters you wouldn't think of needing good Int. scores. Especially fighters. With only 2 skill points per level for the class, if I put a 14 in Int., I've doubled my available skill points at each level.
I use the same reasoning for Con. My fighter types rarely have higher than a 12 Con. They already have good Fort saves so they don't need the bonus for that. And if I'm rolling a d10 for hit points, that +1 hit point only represents a 10% increase over my maximum potential hit points each level. But for a Wizard, a 16 Con means that I can increase my hit points by at least 75% EVERY LEVEL!
In many ways this might be backwards thinking and perhaps I should be looking with more of an eye toward accentuating my positives. But hey, it makes for interesting characters.