Ab workout suggestions

I've been working my abs more in my workouts lately, but I am really only seeing structural differences in the upper portion. I've been doing planks, and crunches, and all kinds of leg lifts and such, but the lower half is still sticking out a bit...
I know it just takes time, and I am all in for the long haul, but does anybody have any suggestions on what to add to my regiment specifically for the lower abs...I am talking about the section going from your belly to your personal region...