You as a player may be interested in a relatively Randomized Ability Roll when you want to increase the level of challenge in the game, by not rolling up perfect scores every time (no more three 18's), but you also want a character who is very playable in the class you have chosen.
I use a method where I take the "very first roll above 81" (that's at least as good as most NPC adventurers in BG) where the primary ability you've chosen for the PC is also above 12. Then I deduct up to 3 points from any ability, and add up to 3 points to any other ability. Quick and dirty, and it usually works.
It gives me a character with the primary attribute of 16 to 18 and as many as 3 points added to a couple other stats that you may consider to be important. Often comes up with some very interesting and playable characters.
There are other variations on this, which I will discuss if this generates sufficient interest.