I tend to make major changes with my hair. My hair is naturally blonde. At the end of 2006, I dyed my hair VERY red. I also had a haircut similar to Katie Holmes. Then, in May of last year, I got a short pixie cut and bleached my hair blonde. Now, I have a short crop/bob with light and dark blonde highlights. I usually don't color my hair so much, but I do like changing my cut.
I love my crop with side-sweeping bangs (and slightly shorter in the back). It is a little shorter than chin length. with my thin hair, I need to blow dry to get any volume, but it is so short it only takes about 3 minutes. On casual days, I just let it air dry. I have naturally wavy hair, too, so it looks kind of funky if I don't even brush it.
What is right for you will depend on your face shape and hair texture. I have an oval face, which tends to work with any cut, but very thin hair. This means my best cut is short. You need to go to a good hair stylist that can determine what would look best for you.
If your hair is thinner, you might want to just go for a bob or a shorter cut. It's fun to change things up!