My main formats are 5x12, 8x10, and 6.5 x 8.5.
I was inspired by several articles on Tillman Crane in View Camera a few years ago and by Michael Mutmansky's Ireland pictures on his website to shoot the 5x12 format. 8x10 was just a big step up from 4x5. I tried a little 5x7, but found that the negatives just didn't look quite right to me. Then I started looking into whole plate and got hooked again.
I find that these formats suit my way of seeing more than any others. I don't care anymore if people think I'm nuts. Life is too short to worry about that.