Oh, what a great question and such great answers, too.
I find that my style has evolved a lot, especially recently.
The one block I always go back to is "blocks around blocks". It really is just a courthouse steps type of block, but I only do 2 or 3 steps around and often make the center a fussy cut or an applique block.
I have seen a lot of variations of this block popping up on blogs lately and I always love everyone's take on it.
Even when I make the same block in two different quilts I use different colors. I don't like making the same exact quilt twice!