Most of my AD&D/D&D3E and now T20 characters use the standard 4d6 six (or eight) times, dropping the lowest die from each, assign as desired.
On occassion, especially if we've got extra time, I will allow players to roll 4d6 (dropping lowest die, no rerolls) thirty-six times, arranging the results in a six-by-six grid. They then can choose any row or column and use those numbers as their characters' stats, assigning them as desired. It hasn't seemed to allow really high stats, and usually includes a fairly low one that's dealt with simply to gain a really high stat elsewhere. They then have to work with and around the result.
An example:
___A___B___C___D___E___F
a...14 / 13 / 10 / 16 / 05 / 14
b...12 / 11 / 11 / 15 / 18 / 06
c...15 / 12 / 09 / 11 / 14 / 12
d...12 / 11 / 17 / 16 / 11 / 10
e...12 / 16 / 15 / 11 / 17 / 09
f...12 / 14 / 17 / 04 / 11 / 18
None of these stats are exceptional, but they can all be worked into viable characters. Several don't have any really high stats, but they don't have any low ones, either. Column A, for example, doesn't have a single stat above 15, and only one of those, but all of the stats will give the PC a positive modifier. On the other side of the scale, both Column E and Row f have both an 18 and a 17, but they also have to deal with stats that will provide significant negative modifiers.
How the player chooses is up to them, although I do help them work out just the character concept they are looking for. And I get to keep the matrices that they rolled up, usually using the stats for NPCs later (hey, why let all that work go for naught?)
Simon Jester