We tend (two of the three DMs in our group) to when not playing society etc, roll 4D6 drop the lowest, two sets. This is basically because we like a heroic stature for characters but also because you have a more unique organic character, rather than a cookie cutter fighter, or rogue etc.
If a set has less than around +2 overall we discount them and then you pick which of the two sets you want.
Stats go wherever you want.
On the whole if I was to put all six players characters up from my FR campaign you would be hard pressed to say he/she is more powerful stat wise than the other one as they 90% of the time get a fair spread.