Standard would be just like a normal post. An aside is a special type of post and typically does not display a title. The "gallery" will show a featured image from the gallery you insert into the post, with a line underneath saying, "this gallery contains X photos and if you click on that link, it takes you to the gallery page that then shows all the images.
I tried them all on my test blog at http://flippingtestblog.wordpress.com/ if you want to take a look. There seems to be some bugs though with the gallery thing as it took several attempts to get it to work and the editor would become completely unresponsive and I would have to refresh the page losing my changes. None of the buttons worked.