I always played the character I was rolled, but I didn't like having my role determined for me before I started playing. My favorite method of generation was roll 6 3d6s, and assign how you like. That way, I could play the role I wanted, but probably have some deficient stats.
What some people might not realize is deficient stats HELP you play a more interesting character. They aid in roleplaying. If your character has 6 charisma, what does that mean? Well, mechanically it means that people don't like talking to him, but why? Is he very ugly? does he constantly stink of rotting milk? is he rude and obnoxious? Any of those things (and probably a slight mixture of all 3) tell you why he has low charisma.
To facilitate generating characters faster, when my friends and I were making new games every week, we used a "house special" setup, where characters could choose the stats 6,8,10,12,14,16.. Requiring them to pick a big deficit, and just allowing them to do it quickly.