I generally play the game through the way it was meant to be - though I do twink my chars to high heaven in the process. Sometimes I WOULD rush them, but even when I want to I normally can't, as my friends don't get on when I do any more. As a result, I slap a Khalim's Will on my char, take them through acts one and two - by the time I finish act 2, I'm usually anywhere between level 20 and 24. Closer to 20 if it's a char that's weak levelling at that point, 24 if they have a powerful spell available that early on - because if they can kill everything easily, I start taking them into large games to move forward and get the waypoints, picking up massive exp on the way.