whats everyones views on the best core exercises?

like for the lower back you got hyperextensions and of course deadlifts, but what else?

and for the abs? whats some good exercises to really strengthen these and a good way to trim a lil fat off the obliques? besides cardio

i've had the hardest time getting the lower abs to show and this spring i really wanna show off what i have so i am looking to make a really good workout program

thanks for any input in advance