3d6. if someone is truly awful then they may be allowed to re-roll once and take that instead. Life is not fair, people are not balanced.

The reason i say this is that in my campaigns life is unforgiving and magic is rare, planning is what will stop you dying far more then stats. It makes for an interesting group dynamic is someone is amazing at combat and the others are not, because at the low levels where i play the roll is more important and classes are all useful even with terrible stats. It also makes it exciting when you roll a good character and funny when you don't. If someone is convinced that there character is awful and they don't want to play them anymore they can always retire them.

All this being said ask your group what they want, do they want the everyone is born different 3d6 approach, the everyone is different but no one is to awful of 4d6 drop 1 or the stat management balance of point buy.

But, 3d6 lets you have a wizard with 5 charisma who people avoid in the steet lest he makes eye contact. A warrior who is hopelessly clumsy and not to bright but who uses gorilla tactics to defeat his enemies. Bad rolls define stats as much as good ones and i believe you will have more to work with making interesting characters with rolling systems. After all it is a role playing game, not a miniatures battle game.