Yeah, I'm not doing much situps or crunches. If I do, I either have my hips and knees both at 90deg (like sitting in a chair), or I put the bottoms of my feet together and drop knees to the side (like how lions sit). Both of these really isolate. But I don't like them cuz they're not realistic to what I'd encounter in real life. Now I do hanging leg lifts, knee to chest, knee to elbows (even tho that website says they're bad). However, I refuse to do the hanging windshield wiper because it stresses the lumbar spine discs. I've been meaning to post pics of my abs, I just need to even them out (left side hypertrophy, right side needs to catch up). You can actually get away with not doing any ab exercises if you brace your core before doing any other workout.
Jae