I want to cut all my hair off? Good idea?

Ok, so right now my hair is like this but a little longer (to the end of my neck)….

http://www.myhaircuts0o0com/blackhairstyle/straight_short_hair.jpg

it's really annoying! the sides are short, my ends are dead, i have to straighten it every morning and it's too much…

I was thinking about cutting it all of like this maybe…

http://z.about0o0com/d/beauty/1/0/0/s/rihanna.jpg

or just rihanna's hair cut, but i have kind of nappy hair in the back?? and i'm afraid it won't look so good…..

i have beyonce's skin complexion, i have african-american hair, yeah…gimme yer opinions?