[QUOTE=MissJecka;1103274]Ditto. If I do crunches, I feel it mostly in my neck. My personal trainer used to tell me that it was because I was pulling on my head or going forward rather than "up" but no matter how he adjusted my form, I still would hurt in my neck rather than my abs. (I still do side-crunches though, which I do feel in my lower obliques.)
I love planks and do so many varieties of them because they are AMAZING at strengthening your core and even arms! :)[/QUOTE]
QFT. Crunches are basically useless. Your core is supposed to support and balance you when doing other movements, so lying on the floor half-assedly squeezing them a little bit is a waste of time (and, as you mentioned, often an unnecessary strain on the neck). Side-crunches for the obliques are better, also "leg lift" crunches to work the lower abs usually work pretty well if youre flexible enough that you can get your legs up without straining your low back.
I'm a bellydancer so I'm always looking up new stretches and exercises for the pelvis and core muscles. If you like planks and working the obliques, I recently found this exercise and I looooove it:
[url=http://www.youtube.com/watch?v=EOML95SuqUc]A Core Exercise for Belly Dance: The Twisting Plank - YouTube[/url]