I run low powered human centric campaigns.
Humans roll 4d6 drop lowest 3 times and 3d6 4 times - keep the best 6 stats, arrange as desired.
All other races roll 4d6 drop lowest 2 times and 3d6 5 times - again keep the best 6 stats, arrange as desired.
In both cases re-rolls are done if character bonuses are less than a total of +4.
This gives me exactly the feel I want in the PCs running around my Greyhawk campaign.
Attribute Rolling
Re: Attribute Rolling
I prefer straight 3d6. Good random spread of attributes, and a high value is cherished, this also allows low values to be looked past a little, and I factor these weaknesses into encounters.
I do though, prefer to allow each PC to improve any one attribute every 3 levels by 1 point or their lowest attribute by 2 points, where the lowest attribute tends to be the least influential as per class/race combo anyways (think of a fighter with high physical attributes, but a 5 in INT. Bumping INT to 7 is really not going to alter to terribly much, but it influences players to think about their weaker attributes more). This is just one implementation of self-improvement and long-term options of customization I like to add to the game.
I do though, prefer to allow each PC to improve any one attribute every 3 levels by 1 point or their lowest attribute by 2 points, where the lowest attribute tends to be the least influential as per class/race combo anyways (think of a fighter with high physical attributes, but a 5 in INT. Bumping INT to 7 is really not going to alter to terribly much, but it influences players to think about their weaker attributes more). This is just one implementation of self-improvement and long-term options of customization I like to add to the game.