I tried a few times to have a post format, but I got lazy copying and pasting. I even had the tektek toolbar for firefox, but even then I wasn't interested in making my own post style anymore.
Personally I think minimalism is key to making a good format. Too much filler text is the only thing that annoys me. I can take a lot of flashy gifs or pictures, whatever, but I get pretty annoyed with a lot of text, especially when the only thing someone posts is a heart or something.