I've used minis before, but answered no, as I no longer do.
I found it caused a few problems.
First, it slowed combat down measurably.
Second, people started... playing different. It became less roleplaying, more rollplaying, to use the old catch phrase. "Ok, if I move to this grid, I'll get AoOed, but if I dont, next round the giant will threaten me... But if I do, even if I survive the AoO, our mage will then have to re-plan his cone spells... hmmm..." Not the type of game I want.
It's expensive, if you want to use real minis, and confusing if you don't ("Ok, so the green jellybeen is an ogre, and the..." "Wait, I thought the green jellybeen was me...").
I'll sometimes, for a complex battle scene, draw a quick sketch on a sheet of paper... Nothing major, "Ok, this circle is the pit of acid, these three X's are skeletons, this big "D" is the dragon, these little circles are you guys...", but it doesn't update with the battle, or anything, it's just to set the scene.